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June Gardening Checklist

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Fellow Gardeners,

The information, dates, and techniques in this are as accurate as I can currently offer. During the past three decades, I have cared for, nurtured, and observed tens of thousands of plants. With the help of many gardening friends, I have attempted to offer on these pages some useful information to help you with your own garden. Gardening is sharing. Any corrections, comments, or suggestions are appreciated and will improve future information.

Table of Contents:




Annuals:

June is the prime season for warm-season annual plants. As the temperatures warm up, these annual flowers are setting up for a season of colorful blooms. Make sure you get them planted soon before the mercury really rises! Here are some annual plant tasks for your June gardening checklist.

This is a month for warm-season annuals. The nights are consistently warmer, the days are longer (and sunnier!), and the thermometer is rising.

Warm-season annuals are in abundant supply now. If you didn’t get them planted in the last month or two, I suggest you get them planted now before the really hot weather of July or August. Some great annual choices include celosia, petunia, lobelia, verbena, marigold, ageratum, cosmos, impatiens, coleus, torenia, and begonia.

Some real hot, hot, hot weather sizzlers include dahlias, zinnias, gomphrena, salvia, portulaca, cleome, and lisianthus. This is a good month to plant these since they absolutely love hot temperatures.

Because of their quick growth and heavy flowering potential, annuals need more fertilizing than most other plants in the garden.

Keep deadheading (removing spent flowers) from annuals every day to help them continue blooming abundantly.

For more information, watch and learn Spring Annuals with Dalia Brunner



Geraniums:

This group includes ivy geraniums, zonal geraniums (also called “common” geraniums), Martha geraniums, and the various scented geraniums that are annuals, but does not include true geraniums (sometimes called “hardy” geraniums), which are discussed under Perennials.

Ivy and zonal-type geraniums are still blooming well now. Keep up with removing spent flowers regularly to encourage more bloom.

Martha geraniums have finished up their big spring bloom. Unlike ivy and zonal types, these are not generally everblooming plants. With regular deadheading, a bit of shade in hot inland gardens, and continued feeding, you will be able to encourage a few more sporadic blooms through summer. Keep removing any spent flower clusters.

Ivy and zonal geraniums do not like heavy pruning. To keep the plants shapely and vigorous for a longer period of time, prune back a few long stems every month or so from now through fall, but never very many at one time.

Continue fertilizing all geraniums (except most scented types) regularly with a balanced fertilizer. Annual geranium flowers prefer slightly acidic soil, so periodically alternate feedings with an acid fertilizer, such as cottonseed meal.

Budworms may still be attacking the developing buds and new leaves. If necessary, spray with BT on a regular basis.

Rust may continue to be a problem in some gardens, especially on zonal and Martha varieties. However, it is usually only a springtime issue, and with the warmer weather approaching, the rust problems should be nearly over.



Sweet Peas:

Annual sweet pea plants are about done for this year. If they are still looking good and blooming—enjoy them! They will probably be showing quite a bit of heat stress now, particularly at their bases, where yellowing and drying will eventually become overwhelming.

Powdery mildew commonly develops on the foliage at this time of the year. Rather than attempt to control it, which will prove impossible, this is a sign that the season is nearly over.

If you have any particularly outstanding varieties, you can attempt to harvest some seed and store it until this fall. However, sweet peas often do not grow “true” from their seed.

For more information, watch & learn: World-Class Sweet Peas with Steve Hampson



Poinsettias:

You should have pinched the tips of any new poinsettia growth last month. If not, do so right away.

Keep fertilizing the plant often with a well-balanced food to encourage growth.

Watch for whiteflies and treat as needed.



Wildflowers:

It is far too late for annual wildflowers now. If you will be planting again this winter, keep the area free of weeds between now and then. If the area is free of other plants, do not water it. Irrigations will only encourage weed growth.



Fruiting Plants

June gardening tips are primarily about monitoring and watering your fruiting plants. There aren’t many fruit plants you can plant in June because the weather is getting too hot. However, there are plenty of maintenance tasks to do this month to keep you busy!



Strawberries:

Fertilize regularly. Periodically alternate with an acid fertilizer, like cottonseed meal, to keep the soil pH low.

If strawberries attempt to grow runners, pinch them off so that they continue to focus energy on fruit. Keep feeding your strawberries, and they will continue to produce more fruit.

Watch for signs of spider mites by checking the foliage periodically. Occasionally rinsing the leaves with overhead watering will reduce this pest problem considerably.

Bait, trap, or handpick snails and slugs regularly to avoid fruit damage.

For more information, watch & learn: How to Grow the Best Strawberries with Sarah Smith



Grapes:

New growth on grapes is slowing down now as the plants direct their energy toward fruit production. Tie or support the canes as needed to prevent tangling or damage later.

Assuming you’re using a granular organic product, you should be feeding grapes every 6-8 weeks following the first application, which was applied when the new growth was just starting. Following this schedule, four applications are usually sufficient. Grapes need a well-balanced fertilizer that contains trace minerals. Organic products are generally a good choice.

Irrigate regularly and deeply in the warm summer temperatures.



Shrubs and Vines:

Many of our beautiful shrubs and vines in California are still blooming beautifully and growing profusely in June. It's essential to keep them well-watered and mulched now and through the summer to help them survive the heat. June is not a great month for planting most shrubs since we’re shortly heading into the hottest part of the year. The heat of summer can be stressful for plants, especially ones that aren’t well established yet. Here are a few checklist tasks for June shrub and vine gardening.

Bougainvilleas are setting flowers now and growing quickly in the warm weather. Avoid pruning them now, which will interfere with their bloom. Bougainvillea is the exception to the rule, and June is an excellent time to plant these heat lovers.

For more information, watch & learn: Hardy Flowering Shrubs with Dalia Brunner



Azaleas:

Keep azaleas well-irrigated now that the weather is warming up.

Azaleas are shallow-rooted and will dry out quickly. Avoid cultivating or allowing other plants to grow under or in competition with the roots of your azalea.



Camellias:

You will probably be toward the middle or end of your camellia shrub fertilizing for the year. The first of three feedings to your camellia should have been applied about 4-6 weeks after it finished blooming. The second feeding is 4-6 weeks after the first, and the final feeding is 4-6 weeks later again.

If you did not apply a thick, fresh layer of organic mulch under your camellias last month, do it now. This mulch will keep the roots cooler during the warm summer months, improve the soil quality, and reduce watering requirements.

Except for a couple of late-blooming Japanese camellia varieties, most have finished their bloom period for the year.

Keep camellia flowering shrubs well-irrigated now that the weather is warming up.

Camellias are shallow-rooted and will dry out quickly. Avoid cultivating or allowing other plants to grow under or in competition with the roots of your camellia.

For more information, watch & learn: Gardening 101 Series | How to Plant & Maintain a Camellia



Gardenias:

Gardenias should still be blooming and growing well this month.

Keep them well-fed through the summer months. Use a fertilizer with trace minerals, such as most organic types, and alternate this with an acidic formula to keep the pH down.

If the leaves of your gardenia bush are showing signs of green veins with yellow areas between the veins, especially on the new growth, they need additional iron. Use chelated iron as a supplement to the regular fertilizing program of your gardenia.

For more information, watch & learn:
Gardenias for Southern California with Nicholas Stadden
How to Successfully Grow Gardenias with Sarah Smith



Hydrangeas:

Hydrangeas should still be blooming beautifully.

Keep feeding hydrangea shrubs to produce more new growth (which will bloom next year).

Remove any flowers that have faded by pruning as far as halfway down the stem below the flower.

Only prune stems that have flowered this season; leave all other stems alone since they will flower on their branch tips next season.

For more information, watch & learn:

Blooming Hydrangeas with Sarah Smith



Roses:

This is still a big bloom month for roses, but by now, the “first bloom” is about done, and the side branches are in bud and blooming. The flowers may be just a bit smaller but still terrific.

Old-garden roses (also called heirloom roses) only bloom on “old wood.” This means that they only produce flowers on the tips of the branches left in place from the previous summer. By contrast, almost all modern roses bloom on “new growth.” Old-garden roses (popular examples are ‘Cecil Brunner,’ ‘Grus an Auchen,’ ‘Reine des Violettes,’ and ‘Lady Banks’ Rose or Rosa banksiae) need their annual pruning immediately following their big spring bloom–about now. Do not prune these varieties again in the winter, or you will eliminate most of the flowers for next year.

Roses are heavy feeders; continue fertilizing them regularly.

Do not use soil-applied fertilizers combined with a systemic insecticide. These products are very disruptive to soil life (beneficial microorganisms, bacteria, mycorrhizal fungi, earthworms, etc.) Many rosarians also believe they reduce the vigor of the rose.

Granular, well-balanced, organic fertilizers work especially well for roses, and most of these will encourage beneficial soil life.

Keep deadheading roses as they fade.

Stay on the lookout for pests, although by now, pests will be less of an issue.

One pest that is quite common now, especially in coastal gardens, is the rose slug. Not a slug at all (or even a caterpillar, which it resembles), this is the larval form of a fly relative called a sawfly. These little green caterpillar-like pests are hard to spot but chew on the undersides of shrub rose foliage. If you have them, you’ll be seeing lots of irregular holes eaten through the leaves. Neem oil will work on them, as will organic pyrethrin sprays, but the applications must be thorough, frequent, and applied to the undersides of the leaves.

Disease problems, especially in inland gardens, should be much reduced by now and through the rest of summer.

Irrigations should be frequent now as the weather warms and the days lengthen.

Hose off the foliage of roses frequently. Contrary to popular myth, this will actually reduce the likelihood of powdery mildew and keeps the foliage clean and healthy-looking.

Weed as needed, but avoid most herbicides around roses.

June is another good month to get out and visit other rose gardens. Nearby, visit Rose Hills Memorial Park (Whittier) and the Richard Nixon Library (Yorba Linda).

For more information, watch & learn: How to Prune Your Roses With Laura Weaver,, & How to Plant and Care for Roses & How to Maintain and Care for Roses & The Best Fragrant Roses with Laura Weaver & How to Grow Healthy Roses with Suzanne Hetrick



Wisterias:

June is the first month to cut back established wisteria vines. This is the first of three annual prunings. A good pruning schedule for your gardening checklist is June, August, and December.

Cut any and all unwanted wisteria new growth to three buds above last year's resting point. The point where the current year’s growth began and last year’s ended can be located by noticing the change in the stem/bark color. This pruning should be done to encourage flower bud development and to contain the size of the plant.

You can take cuttings, from softwood parts of wisteria vines, for rooting if you’d like.

Established wisterias are better with only an occasional deep summer watering and little, if any, fertilizer other than possibly iron (to correct chlorosis). Wisterias are large, aggressive vines; additional water and fertilizer will only create more rampant growth and more pruning needs.

On young plants, continue guiding the long, twining stems carefully in the direction that you want.

Also, on young plants, be sure to provide plenty of water and fertilizer to encourage quick coverage and deep roots.

If you haven’t already, cutting off the small developing seed pods now will make a more attractive plant through the summer.



Trees:

Most trees are doing well in June and don’t require much maintenance. But, as the hot weather comes around, you may need to increase how often you water your trees. Check soil moisture regularly to ensure timely irrigation. Lots of birds are still nesting in June, so avoid pruning trees this month. June is not generally a great month for planting fruit trees, but there are a few subtropical types that will do fine if planted now. Add these tree maintenance tasks to your gardening checklist for June.

Deciduous Fruit Trees:

With the warming weather, be sure to monitor the soil moisture and irrigate as needed.

Early varieties of peaches and nectarines may be ripening this month, and most apricots are also ripe now.

If your deciduous fruit trees did not perform a “drop” of some of their young fruit last month, they may now. Remember, this is a normal process since the tree cannot usually support all of the fruit that it originally sets.

The best time to thin any remaining fruit is after the “drop” is completed. This is one of the most difficult things for a gardener to do. However, well-spaced fruit will develop into a higher-quality crop, and the fruit size will be much larger as well.

Birds often take their toll on ripening fruit, especially soft varieties like peaches, apricots, nectarines, and plums. If this toll is too great, drape thin nylon fruit tree netting over the canopy of the tree a few weeks before the ripening date. Remove the netting once all the fruit has been harvested.



Citrus:

Citrus trees are still growing well this month, and the leaves should be a healthy green color.

Continue to fertilize citrus trees for another month or two. Use a fertilizer rich in trace minerals like iron, zinc, manganese, copper, and others. These ingredients are usually well represented in organic fertilizers.

Be attentive to irrigation now that the weather is warming up. The best application method is probably by flooding the root basin and letting it soak in once or twice. Do not use sprinklers, especially if they wet the trunk of the tree.

Valencia oranges may look ripe, but before you pick them, try a sample. If the sugars have developed sufficiently, then harvest more. If not, wait a few weeks and test again. Once ripe, Valencia oranges will keep on the tree for months.

‘Kara’ tangerines may be ripe by now or very soon. This is about the only summer-bearing mandarin and needs a warm inland location. Tangelos are about ripe now also.

Continue periodically checking for ants. Control them from climbing up the trunk of the tree or onto the branches immediately. Although not directly harmful to the citrus, they “farm” pests like scale, whitefly, and mealybug, which are all common on citrus.

For more information, watch & learn: Growing Citrus in Southern California with David Rizzo & Growing Citrus in Containers with Kathleen



Avocados:

Apply your third and final feeding to avocado trees this month. A mature avocado tree should be given between ½ and 1 pound of actual nitrogen per inch of trunk diameter. (Example: 15-30 pounds of 20% nitrogen if a six-inch trunk; 30-60 pounds of 10% nitrogen if a six-inch trunk, etc.)

Avocados are still growing, and they should look pretty good.

Irrigate as needed to keep the soil moist but not wet.

This is a very good month for planting avocados. Being sub-tropical plants, avocados prefer to be planted at the beginning of the long, warm part of the year.

Don’t be alarmed by a lot of leaf drop on mature plants. Avocados produce a lot of leaf litter nearly year-round. This is a normal condition.

Most varieties will not have fruit ready for harvest this early. However, other varieties are almost ready for picking. Varieties like ‘Gwen’ and ‘Whitsell’ often have fruit at unusual times.

Be sure to keep a very thick blanket of mulch, compost, or fallen leaves under mature avocados at all times. Avocados need a cool root-run for good health.

For more information, watch & learn: Edible Gardening: How to Grow Avocados in Southern California with Sarah Smith



Subtropical Fruits:

Subtropical fruit trees are all growing well now.

If you didn’t last month, fertilize now with a general-purpose organic fertilizer. Most tropicals and sub-tropicals have a higher need for trace minerals like iron, zinc, manganese, and others. Organic fertilizers generally contain lots of these trace minerals and work especially well in the warm soil temperatures present now.

June is a good month to plant these heat-loving fruit trees, but make sure to add regular watering to your gardening checklist to help them establish.

Watering should be frequent now, but most tropicals and sub-tropicals are particular about quick soil drainage.



Perennials:

June gardening tips for perennials are mostly focused on maintenance, though there’s still some time for planting perennial flowers. If you are planting perennials this month, be sure to keep them well-watered as these young plants head into the warm summer months. Try to avoid overgrown or root-bound plants, as they will be harder to establish.

Keep fertilizing your perennial plants. The frequency and amount will depend upon the formulation that you are using. If you have been building up your soil health, your fertilizing duties will be greatly reduced.

Removing the many spent or old flowers regularly will help them to produce more new flowers. Add the deadheaded blossoms to your compost bin.

Irrigating your perennials now is more important than it was just a month ago. The heat of summer is approaching, and there are no rains to help you out. Your perennials will respond well to careful irrigations now.

Subtropical perennials are at their happiest now and over the next two or three months. This is a good month to plant these heat lovers, too.

For more information, watch & learn: Gardening 101 Series | How to Use Annuals vs. Perennials with Lynn Hillman & Gardening 101 Series | Pruning Lavender & Perennials with Dalia Brunner



Clematis:

Many clematises are still blooming. Keep them well-fed with a balanced organic fertilizer to keep them going.

Clematis prefer cool roots, especially during the summer months. If you can, grow another shrub directly to the south of your clematis to provide some shade over the roots. Alternatively, place a large modern outdoor planter on the south side of the plant.

To insulate the roots even more and moderate the warm summer soil temperatures, maintain a thick 3-4 inch layer of organic mulch over the roots at all times, especially now.

As the weather warms up, apply more frequent irrigations.

If you are growing a spring-only flowering variety (not as common in Orange County), these should be pruned soon after their spring bloom is finished, which may be this month.



California Native Plants:

Be very cautious irrigating most of our California native perennials during the summer. Most of these are adapted to a “winter wet/summer dry” moisture cycle. Excessive irrigations now (especially in soils with a clay content) will certainly cause problems.

For more information, watch & learn: California Native Plants for Your Garden with James Maxwell, Success with Native Plants with James Maxwell, and All About Our Native Milkweed



Fuchsias:

Your fuchsia plants should still be in full bloom now.

Keep fertilizing regularly with a balanced fertilizer, or one slightly higher in phosphorus, to promote blooms.

Keep the plants well-watered, especially during a warm spell, and pay special attention to any plants in hanging baskets.

During any particularly dry, hot, and windy periods, misting the foliage a couple of times is very beneficial. If the soil is already moist from an early morning watering, be careful not to soak the soil again, or you may encourage root diseases.

Groom the plant periodically by removing dead flowers and any developing seed pods.

Watch for Fuchsia Gall Mites again this month. These nearly invisible pests are a serious threat to fuchsias. Look for any signs of puckered or distorted new growth. If you discover any, pinch it out and dispose of it immediately. A pesticide treatment is usually required.



Groundcovers:

Cool-season groundcovers are showing heat stress, especially in warm inland gardens and on south-facing slopes. Keep them irrigated and mulched.

Warm-season groundcovers are growing and blooming. Keep them irrigated as the weather warms.

If not already done, mulch most groundcover areas now to reduce weed growth, cool the roots, improve soil quality, and reduce summer irrigations.

For more information, watch & learn How to Plant & Grow Groundcover with Dalia Brunner



Bulbs, Rhizomes, Tubers, etc.:

Spring bulbs are long-finished flowering by now, but several warm-weather varieties are putting on a good show now in Orange County. These include some alliums, calla (in cool and moist situations), galtonia (summer hyacinth), gladiolus, hippeastrum, many true lilies, tigridia (recommended), tritelleia (recommended), and Watsonia.

Caladiums are continuing to sprout and grow nicely now. Keep them watered and fertilized and in bright but indirect light with shelter from winds.

Now that the soil is very warm, it is still a good time to plant tuberose tubers that you bought at the nursery in January or February or from those you dug out of your garden last November. Give them a sunny site and slightly acid, well-drained soil.

As spring bulbs finish blooming, do not hurry to cut back the foliage or ignore the plant. Keep the leaves in place and continue watering until the leaves naturally turn brown and dry, then you can cut them off. These leaves are sending energy to the bulb for next season.

For one-year bulbs (like most anemone, crocus, hyacinth, muscari, ranunculus, and tulips), after they are done blooming, you can pull them and toss them out.

For more information, view Gardening 101 Series | How Do I Plant Spring Bulbs?



Bearded Iris:

Bearded irises should have finished their first bloom by now.

Trim off the faded flower stalk just above the foliage when the last flower fades.

If you are growing any of the new “repeat-blooming” varieties, they may cycle again in as little as another month or two. Keep feeding these re-bloomers aggressively. Older “once-blooming” varieties can have their feeding reduced in half. Any fertilizer labeled for roses (but not with insecticides or other added ingredients) will do fine.



Dahlias (Tuberous Types):

Dahlia plants should be in full bloom, robust, and vigorous now.

Regularly cut off spent blooms to make the plants both look better and set more flowers.

Keep the taller varieties carefully staked to prevent the heavy canes from toppling over. Heavy natural cane bamboo stakes work well.

Dahlia perennials need water regularly and deeply, especially as they grow larger and the weather warms. Flooding the soil works best; overhead watering will cause broken stems and mushy flowers. Missed waterings now will cause gaps in the flower development later in the season.

Fertilize them regularly throughout their growing and blooming period. Use a liquid or granular organic fertilizer that is low in nitrogen and high in phosphorus. Fish bone meal is excellent.

For more information, watch & learn Lew Whitney's Secrets to Growing and Maintaining Dahlias



Cannas:

Cannas should be flowering well now.

Keep them well watered; cannas do not like dry soil.

As cannas flower, you may notice that each stalk produces a cluster of flowers at the top. After this cluster finishes, the stalk grows a few more inches and produces another cluster. In some varieties, this can go on for four or five clusters and last almost two months from beginning to end. When the last cluster of flowers has finished, cut the entire stalk to the soil. This stalk will never bloom again, and cutting it down will encourage more stalks and flowers to grow. Keep this process up all summer for the best results.



Tuberous Begonias:

Plants are still growing and should have buds and maybe even some flowers. Some gardeners pinch out the first set or two of flowers to focus more energy on the growth of the plant.

Most tuberous begonias produce both male (single) and female (double) flowers separately on the same plant. The double flowers are much showier, and many people pinch off the single (male) flowers as they appear.

Keep fertilizing regularly. Tuberous begonias are heavy feeders, especially in containers. Use a well-balanced fertilizer and periodically mix in an acid fertilizer to keep the soil pH low.

Keep them well-watered but not soggy. The soil should be rich and well-drained. The surface of the soil should dry slightly between watering.

If in a breezy location, staking upright varieties with a small bamboo stake will reduce the possibility of breakage.

Pinch off faded flowers regularly and rotate container-grown plants to ensure even growth.

If powdery mildew appears, treat it by improving air circulation around the plants. Usually, this will correct the problem; if not, use a fungicide.

For more information, watch & learn: Specialty Begonias with Sarah Smith



Tropicals & Subtropicals:

Tropical and subtropical plants are all growing well now, although many will not be in bloom yet. Don’t worry; they’re just waiting for longer days, even warmer daytime temperatures and especially warmer nights.

If you didn’t last month, fertilize now with a general-purpose organic fertilizer. Most tropicals and sub-tropicals have a higher need for trace minerals like iron, zinc, manganese, and others. Organic fertilizers generally contain lots of these trace minerals and work especially well in the warm soil temperatures present now.

This is a very good time to plant or transplant palms and cycads.

This is a good month for planting these heat lovers, but keep them well watered to help them establish.

Watering should be frequent now, but most tropicals and sub-tropicals are particular about quick soil drainage.



Ferns:

Ferns are pretty happy for now; you just need to make sure you keep them well-watered. You still have a bit of time to plant, re-pot, or transplant ferns, but be quick.

Hurry, but there is still time to re-mount and/or divide staghorn ferns that have outgrown their boards or outdoor pottery planters

Continue fertilizing your ferns. Use a mild, organic fertilizer on ferns and alternate periodically with an acid type, especially in high pH soil. For most common varieties, try blood meal alternated every third feeding with a cottonseed meal.

Irrigate most varieties regularly according to weather and the growth of the individual plants. Delicate fern varieties appreciate an occasional misting of the foliage, especially during warm, dry, or windy periods.

Keep checking for pests. Scale can be a problem and often goes undetected. It is often associated with ants, which need to be controlled as a part of any treatment program. On other ferns, especially staghorns, check carefully for early signs of spider mites.



Vegetables and Herbs

June is the time to get those warm-season veggies in the ground, and it’s not too late to plant herbs before the heat really kicks off. Those Mediterranean herbs that love summer heat should be happy in pots outside all summer. Here’s your June gardening checklist for the veggie and herb garden.

Vegetables:

Almost any warm-season vegetable can be planted now. Plant beans, chard, cucumbers, eggplants, lima beans, okra, peppers, squash, and tomatoes from transplants or seeds. Corn, melons, pumpkin, and sunflowers are best planted from seed.

Beets, carrots, chard, radish, and possibly turnips can be planted just about year-round. All but chard are planted from seed only. Be extra diligent about keeping the small seeds watered in this hot weather.

Along the immediate coast, gardeners can cheat a bit and still grow cool-season crops like arugula, lettuce, and some members of the cabbage family. June is the best month for these coastal gardeners to attempt real heat-lovers like corn, melons, peppers, and pumpkins. Grow them in the hottest spot in the garden, such as in front of a hot, light-colored, south-facing wall.

June is also a good month for planting the real heat lovers like corn, eggplant, jicama, lima beans, melons, okra, peppers, and pumpkins, now that the soil and night temperatures have warmed.

Plant pumpkin seeds for Halloween fruit. July 4 is the latest reliable date that seed can be started for a successful Halloween harvest. If you’re growing the “giant” types, it may already be too late.

Keep tomato plants trained inside their cages or, alternatively, up stakes or obelisks.

Time is running out to plant melons from seed. Get them in the ground or containers this month.

If growing corn, be sure to keep it continually fertilized and well-watered. Lapses in either will result in a poor yield.

Don’t worry if the first several squash flowers don’t set fruit. They’re male flowers.

Put in successive plantings of many vegetables a couple of weeks apart to ensure a constant, uninterrupted supply for the kitchen.

Keep planting corn from seed this month. Because corn needs to be cross-pollinated, it must be grown in clumps or rows. Twelve plants are about the minimum for good pollination, and twenty or more is even better. Plant crops successively every three to four weeks for a continual harvest. If planted in small groups, hand-pollinating will provide fuller ears.

Since most annual vegetables are shallow-rooted and quick growing, feed them regularly with a well-balanced organic fertilizer.

Keep the vegetable garden well-watered during the hot summer.

If you planted bulbing onions last fall, June is the ideal month for harvesting.



Herbs:

This is still a good time to plant basil. Be sure to pinch the flowers off of basil and many other herbs as they develop. Flowers not only reduce the quantity and size of the foliage but often change the flavor as well.

There’s still time to plant the annual summer savory! The perennial winter savory can also be planted now; however, the flavor of the perennial version is usually considered inferior.

Many perennial herbs can be kept in outdoor planted containers nearly year-round, but particularly during the warm summer. These include marjoram, oregano, rosemary, sage, thyme, catmint, catnip, chamomile, comfrey, feverfew, lavender, lemon balm, lemongrass, lemon verbena, St. John's wort, tansy, tarragon, and thyme.

General Gardening Info

Most of your general June garden maintenance checklist consists of keeping your garden watered and fertilizing regularly. Consistent watering starting now through the hottest part of the summer is the key to helping your plants thrive through the heat. Here are some general June gardening tips to look out for this month.



Beneficial Insects:

Beneficial insects should be abundant in your garden now, especially if you planted a few flowers just for them.

If needed, ladybugs and lacewings can be released again this month.

The population of natural predators and parasites always follows behind that of the pests. They will need some time to catch up with the pests, so be patient.

Giant whitefly is active again, and infestations should be noticeable. Predators and parasites should also be present by now. Check immature whiteflies carefully for signs of parasite activity. If none are found in one part of the garden, remove a few leaves from another plant that has been parasitized and place it carefully into the foliage of the non-parasitized plant.

Flea, grub, and cutworm populations may be present now. Control can be achieved by using various beneficial nematodes. These microscopic worms are applied by mixing them in a watering can, drenching the area, then watering well.

Encourage opossums, which are predators of the common garden snail.

Now that the weather has warmed, spider mites can become problems on many plants, such as citrus, avocado, pine, juniper, ivy, and others. Release beneficial predator mites now for control.

Trichogramma wasps are very effective parasites of caterpillars. If these pests are usually a problem in your garden, a couple of releases of these beneficials will be worthwhile. Space releases 30 to 45 days apart.



Lawns:

If you haven’t already, you still have time to de-thatch and aerate lawns like hybrid bermudagrass and St. Augustine.

Remember, cool-season lawns (fescue/marathon, ryegrass, bluegrass) should be mowed about half an inch higher in the warm months than in the cool months. Keep the mower at this higher setting for the next several hot weather months.

It’s too late to attempt to plant new cool-season lawns from seed. You can still try installing sod, but the risk of disease or dehydration is much higher in the warm weather.

This is still a good month to plant warm-season lawns (hybrid bermudagrass, St. Augustine, etc.) from sod. Most warm-season grasses do not grow from seed and are best only installed from sod.

Continue feeding warm-season lawns through summer and into fall.

Begin reducing the dosage of fertilizer by half in June for cool-season lawns. Too much fertilizer during the warm weather will make these cool-season turfs very susceptible to diseases.



Soil Care:

A thick layer of organic mulch, averaging about two inches, should be maintained on top of the soil just about year-round. Especially with the warm temperature of summer just ahead, this is an excellent time to refresh this layer and add additional mulch as needed.

Applied now, a thick layer of mulch will cool the root systems from the hot temperatures, reduce irrigations by as much as 50% this summer, reduce weed problems, and improve both soil life and soil quality.

We do not suggest the use of very high-analysis fertilizers in a garden, especially phosphorus.

Examples of fertilizers to avoid are synthetic versions with formulations like 10-55-10, 10-30-10, etc. We don’t even suggest the popular 15-30-15 formula. These formulations will inhibit or even destroy much of the soil life that is so vital to healthy, sustainable soil.

We also suggest that you not use soil-applied systemic fertilizer/insecticide combinations (especially popular with roses). These are very damaging to soil life.

Use insecticides only when necessary, and even then, use the least damaging product available. Many of these products move into the soil and interfere with the invisible soil life.

If you can, begin a compost pile or purchase a compost bin. Leaves, clippings, kitchen produce scraps, and many other ingredients can be composted and returned to the garden. Home compost is one of the very best ingredients you can add to your soil. The benefits are huge in the areas of disease suppression, increasing beneficial microorganisms, improving soil structure and texture, nutrient retention, and nematode suppression.

Be sure that, before you put a plant into the ground, you have considered the soil and are doing all you can to improve it and protect its health.

For more information, watch & learn:


How to Prepare Your Soil with Suzanne Hetrick
Gardening 101 Series | What Kind of Soil Should You Use?



Water & Irrigation:

Adjust the interval and duration of irrigations now as we head into the warmer months.

Periodically, rinse off the foliage of the plants in your garden during the summer. Larger shrubs, vines, and trees will need a spray from a garden hose. This will cleanse the foliage of dust and some pollution. Pest problems will be reduced, and the plants will “breathe” easier as well.

For more information, watch & learn: Gardening 101 Series | How to Water Baskets & Pots? with Dalia Brunner & CA Friendly Solutions | How to Install & Use High Efficiency Sprinkler Heads with David Rizzo & CA Friendly Gardening Solutions | Testing Your Sprinkler System with Tracy Wankner



Fertilizer:

Look for signs of chlorosis and apply appropriate fertilizer to correct the problem.

For more information, watch & learn: Why Fertilize & What do the Numbers Mean with Suzanne Hetrick & Fertilizer Tips 1- 2-3 with Suzanne Hetrick

Image Source: https://www.linkedin.com/company/los-angeles-county-arboretum-and-botanic-garden/



Places to Visit:

Gardens that look terrific almost any time of the year include Sherman Library and Gardens (Corona del Mar), The Fullerton Arboretum (Fullerton), Los Angeles Arboretum (Arcadia), Huntington Library and Botanical Gardens (San Marino), and San Diego Botanical Gardens (Encinitas).

Rose Hills Memorial Park (Whittier) is still in full bloom. This is not only a national All America Rose Selections trial garden; it is one of the top rose gardens on the west coast!

The last of the big home garden tours are wrapping up this month.

San Diego County Fair, held in Del Mar for three weeks from mid-June to early July, offers probably the best garden and horticulture presentations of any fair in California. Extensive landscaped displays, dozens of flower and landscape competitions, seminars, and much more make it well worth the visit.



Records, Catalogs, Books, and Organizations:

Summer is one of the best times to attend educational garden seminars and meetings. Many excellent programs are available, and most, but not all, are free with no memberships or reservations required. There is so much going on right now that you will have to pay close attention to keep track of it all!

Make notes in your journal now, especially about water and pests. These will be useful to you again next year.

Fellow Gardeners,

The information, dates, and techniques in this are as accurate as I can currently offer. During the past three decades, I have cared for, nurtured, and observed tens of thousands of plants. With the help of many gardening friends, I have attempted to offer on these pages some useful information to help you with your own garden. Gardening is sharing. Any corrections, comments, or suggestions are appreciated and will improve future information.

Annuals:

June is the prime season for warm-season annual plants. As the temperatures warm up, these annual flowers are setting up for a season of colorful blooms. Make sure you get them planted soon before the mercury really rises! Here are some annual plant tasks for your June gardening checklist.

This is a month for warm-season annuals. The nights are consistently warmer, the days are longer (and sunnier!), and the thermometer is rising.

Warm-season annuals are in abundant supply now. If you didn’t get them planted in the last month or two, I suggest you get them planted now before the really hot weather of July or August. Some great annual choices include celosia, petunia, lobelia, verbena, marigold, ageratum, cosmos, impatiens, coleus, torenia, and begonia.

Some real hot, hot, hot weather sizzlers include dahlias, zinnias, gomphrena, salvia, portulaca, cleome, and lisianthus. This is a good month to plant these since they absolutely love hot temperatures.

Because of their quick growth and heavy flowering potential, annuals need more fertilizing than most other plants in the garden.

Keep deadheading (removing spent flowers) from annuals every day to help them continue blooming abundantly.

For more information, watch and learn Spring Annuals with Dalia Brunner



Geraniums:

This group includes ivy geraniums, zonal geraniums (also called “common” geraniums), Martha geraniums, and the various scented geraniums that are annuals, but does not include true geraniums (sometimes called “hardy” geraniums), which are discussed under Perennials.

Ivy and zonal-type geraniums are still blooming well now. Keep up with removing spent flowers regularly to encourage more bloom.

Martha geraniums have finished up their big spring bloom. Unlike ivy and zonal types, these are not generally everblooming plants. With regular deadheading, a bit of shade in hot inland gardens, and continued feeding, you will be able to encourage a few more sporadic blooms through summer. Keep removing any spent flower clusters.

Ivy and zonal geraniums do not like heavy pruning. To keep the plants shapely and vigorous for a longer period of time, prune back a few long stems every month or so from now through fall, but never very many at one time.

Continue fertilizing all geraniums (except most scented types) regularly with a balanced fertilizer. Annual geranium flowers prefer slightly acidic soil, so periodically alternate feedings with an acid fertilizer, such as cottonseed meal.

Budworms may still be attacking the developing buds and new leaves. If necessary, spray with BT on a regular basis.

Rust may continue to be a problem in some gardens, especially on zonal and Martha varieties. However, it is usually only a springtime issue, and with the warmer weather approaching, the rust problems should be nearly over.



Sweet Peas:

Annual sweet pea plants are about done for this year. If they are still looking good and blooming—enjoy them! They will probably be showing quite a bit of heat stress now, particularly at their bases, where yellowing and drying will eventually become overwhelming.

Powdery mildew commonly develops on the foliage at this time of the year. Rather than attempt to control it, which will prove impossible, this is a sign that the season is nearly over.

If you have any particularly outstanding varieties, you can attempt to harvest some seed and store it until this fall. However, sweet peas often do not grow “true” from their seed.

For more information, watch & learn: World-Class Sweet Peas with Steve Hampson



Poinsettias:

You should have pinched the tips of any new poinsettia growth last month. If not, do so right away.

Keep fertilizing the plant often with a well-balanced food to encourage growth.

Watch for whiteflies and treat as needed.



Wildflowers:

It is far too late for annual wildflowers now. If you will be planting again this winter, keep the area free of weeds between now and then. If the area is free of other plants, do not water it. Irrigations will only encourage weed growth.



Fruiting Plants

June gardening tips are primarily about monitoring and watering your fruiting plants. There aren’t many fruit plants you can plant in June because the weather is getting too hot. However, there are plenty of maintenance tasks to do this month to keep you busy!



Strawberries:

Fertilize regularly. Periodically alternate with an acid fertilizer, like cottonseed meal, to keep the soil pH low.

If strawberries attempt to grow runners, pinch them off so that they continue to focus energy on fruit. Keep feeding your strawberries, and they will continue to produce more fruit.

Watch for signs of spider mites by checking the foliage periodically. Occasionally rinsing the leaves with overhead watering will reduce this pest problem considerably.

Bait, trap, or handpick snails and slugs regularly to avoid fruit damage.

For more information, watch & learn: How to Grow the Best Strawberries with Sarah Smith



Grapes:

New growth on grapes is slowing down now as the plants direct their energy toward fruit production. Tie or support the canes as needed to prevent tangling or damage later.

Assuming you’re using a granular organic product, you should be feeding grapes every 6-8 weeks following the first application, which was applied when the new growth was just starting. Following this schedule, four applications are usually sufficient. Grapes need a well-balanced fertilizer that contains trace minerals. Organic products are generally a good choice.

Irrigate regularly and deeply in the warm summer temperatures.



Shrubs and Vines:

Many of our beautiful shrubs and vines in California are still blooming beautifully and growing profusely in June. It's essential to keep them well-watered and mulched now and through the summer to help them survive the heat. June is not a great month for planting most shrubs since we’re shortly heading into the hottest part of the year. The heat of summer can be stressful for plants, especially ones that aren’t well established yet. Here are a few checklist tasks for June shrub and vine gardening.

Bougainvilleas are setting flowers now and growing quickly in the warm weather. Avoid pruning them now, which will interfere with their bloom. Bougainvillea is the exception to the rule, and June is an excellent time to plant these heat lovers.

For more information, watch & learn: Hardy Flowering Shrubs with Dalia Brunner



Azaleas:

Keep azaleas well-irrigated now that the weather is warming up.

Azaleas are shallow-rooted and will dry out quickly. Avoid cultivating or allowing other plants to grow under or in competition with the roots of your azalea.



Camellias:

You will probably be toward the middle or end of your camellia shrub fertilizing for the year. The first of three feedings to your camellia should have been applied about 4-6 weeks after it finished blooming. The second feeding is 4-6 weeks after the first, and the final feeding is 4-6 weeks later again.

If you did not apply a thick, fresh layer of organic mulch under your camellias last month, do it now. This mulch will keep the roots cooler during the warm summer months, improve the soil quality, and reduce watering requirements.

Except for a couple of late-blooming Japanese camellia varieties, most have finished their bloom period for the year.

Keep camellia flowering shrubs well-irrigated now that the weather is warming up.

Camellias are shallow-rooted and will dry out quickly. Avoid cultivating or allowing other plants to grow under or in competition with the roots of your camellia.

For more information, watch & learn: Gardening 101 Series | How to Plant & Maintain a Camellia



Gardenias:

Gardenias should still be blooming and growing well this month.

Keep them well-fed through the summer months. Use a fertilizer with trace minerals, such as most organic types, and alternate this with an acidic formula to keep the pH down.

If the leaves of your gardenia bush are showing signs of green veins with yellow areas between the veins, especially on the new growth, they need additional iron. Use chelated iron as a supplement to the regular fertilizing program of your gardenia.

For more information, watch & learn:
Gardenias for Southern California with Nicholas Stadden
How to Successfully Grow Gardenias with Sarah Smith



Hydrangeas:

Hydrangeas should still be blooming beautifully.

Keep feeding hydrangea shrubs to produce more new growth (which will bloom next year).

Remove any flowers that have faded by pruning as far as halfway down the stem below the flower.

Only prune stems that have flowered this season; leave all other stems alone since they will flower on their branch tips next season.

For more information, watch & learn:

Blooming Hydrangeas with Sarah Smith



Roses:

This is still a big bloom month for roses, but by now, the “first bloom” is about done, and the side branches are in bud and blooming. The flowers may be just a bit smaller but still terrific.

Old-garden roses (also called heirloom roses) only bloom on “old wood.” This means that they only produce flowers on the tips of the branches left in place from the previous summer. By contrast, almost all modern roses bloom on “new growth.” Old-garden roses (popular examples are ‘Cecil Brunner,’ ‘Grus an Auchen,’ ‘Reine des Violettes,’ and ‘Lady Banks’ Rose or Rosa banksiae) need their annual pruning immediately following their big spring bloom–about now. Do not prune these varieties again in the winter, or you will eliminate most of the flowers for next year.

Roses are heavy feeders; continue fertilizing them regularly.

Do not use soil-applied fertilizers combined with a systemic insecticide. These products are very disruptive to soil life (beneficial microorganisms, bacteria, mycorrhizal fungi, earthworms, etc.) Many rosarians also believe they reduce the vigor of the rose.

Granular, well-balanced, organic fertilizers work especially well for roses, and most of these will encourage beneficial soil life.

Keep deadheading roses as they fade.

Stay on the lookout for pests, although by now, pests will be less of an issue.

One pest that is quite common now, especially in coastal gardens, is the rose slug. Not a slug at all (or even a caterpillar, which it resembles), this is the larval form of a fly relative called a sawfly. These little green caterpillar-like pests are hard to spot but chew on the undersides of shrub rose foliage. If you have them, you’ll be seeing lots of irregular holes eaten through the leaves. Neem oil will work on them, as will organic pyrethrin sprays, but the applications must be thorough, frequent, and applied to the undersides of the leaves.

Disease problems, especially in inland gardens, should be much reduced by now and through the rest of summer.

Irrigations should be frequent now as the weather warms and the days lengthen.

Hose off the foliage of roses frequently. Contrary to popular myth, this will actually reduce the likelihood of powdery mildew and keeps the foliage clean and healthy-looking.

Weed as needed, but avoid most herbicides around roses.

June is another good month to get out and visit other rose gardens. Nearby, visit Rose Hills Memorial Park (Whittier) and the Richard Nixon Library (Yorba Linda).

For more information, watch & learn: How to Prune Your Roses With Laura Weaver,, & How to Plant and Care for Roses & How to Maintain and Care for Roses & The Best Fragrant Roses with Laura Weaver & How to Grow Healthy Roses with Suzanne Hetrick



Wisterias:

June is the first month to cut back established wisteria vines. This is the first of three annual prunings. A good pruning schedule for your gardening checklist is June, August, and December.

Cut any and all unwanted wisteria new growth to three buds above last year's resting point. The point where the current year’s growth began and last year’s ended can be located by noticing the change in the stem/bark color. This pruning should be done to encourage flower bud development and to contain the size of the plant.

You can take cuttings, from softwood parts of wisteria vines, for rooting if you’d like.

Established wisterias are better with only an occasional deep summer watering and little, if any, fertilizer other than possibly iron (to correct chlorosis). Wisterias are large, aggressive vines; additional water and fertilizer will only create more rampant growth and more pruning needs.

On young plants, continue guiding the long, twining stems carefully in the direction that you want.

Also, on young plants, be sure to provide plenty of water and fertilizer to encourage quick coverage and deep roots.

If you haven’t already, cutting off the small developing seed pods now will make a more attractive plant through the summer.



Trees:

Most trees are doing well in June and don’t require much maintenance. But, as the hot weather comes around, you may need to increase how often you water your trees. Check soil moisture regularly to ensure timely irrigation. Lots of birds are still nesting in June, so avoid pruning trees this month. June is not generally a great month for planting fruit trees, but there are a few subtropical types that will do fine if planted now. Add these tree maintenance tasks to your gardening checklist for June.

Deciduous Fruit Trees:

With the warming weather, be sure to monitor the soil moisture and irrigate as needed.

Early varieties of peaches and nectarines may be ripening this month, and most apricots are also ripe now.

If your deciduous fruit trees did not perform a “drop” of some of their young fruit last month, they may now. Remember, this is a normal process since the tree cannot usually support all of the fruit that it originally sets.

The best time to thin any remaining fruit is after the “drop” is completed. This is one of the most difficult things for a gardener to do. However, well-spaced fruit will develop into a higher-quality crop, and the fruit size will be much larger as well.

Birds often take their toll on ripening fruit, especially soft varieties like peaches, apricots, nectarines, and plums. If this toll is too great, drape thin nylon fruit tree netting over the canopy of the tree a few weeks before the ripening date. Remove the netting once all the fruit has been harvested.



Citrus:

Citrus trees are still growing well this month, and the leaves should be a healthy green color.

Continue to fertilize citrus trees for another month or two. Use a fertilizer rich in trace minerals like iron, zinc, manganese, copper, and others. These ingredients are usually well represented in organic fertilizers.

Be attentive to irrigation now that the weather is warming up. The best application method is probably by flooding the root basin and letting it soak in once or twice. Do not use sprinklers, especially if they wet the trunk of the tree.

Valencia oranges may look ripe, but before you pick them, try a sample. If the sugars have developed sufficiently, then harvest more. If not, wait a few weeks and test again. Once ripe, Valencia oranges will keep on the tree for months.

‘Kara’ tangerines may be ripe by now or very soon. This is about the only summer-bearing mandarin and needs a warm inland location. Tangelos are about ripe now also.

Continue periodically checking for ants. Control them from climbing up the trunk of the tree or onto the branches immediately. Although not directly harmful to the citrus, they “farm” pests like scale, whitefly, and mealybug, which are all common on citrus.

For more information, watch & learn: Growing Citrus in Southern California with David Rizzo & Growing Citrus in Containers with Kathleen



Avocados:

Apply your third and final feeding to avocado trees this month. A mature avocado tree should be given between ½ and 1 pound of actual nitrogen per inch of trunk diameter. (Example: 15-30 pounds of 20% nitrogen if a six-inch trunk; 30-60 pounds of 10% nitrogen if a six-inch trunk, etc.)

Avocados are still growing, and they should look pretty good.

Irrigate as needed to keep the soil moist but not wet.

This is a very good month for planting avocados. Being sub-tropical plants, avocados prefer to be planted at the beginning of the long, warm part of the year.

Don’t be alarmed by a lot of leaf drop on mature plants. Avocados produce a lot of leaf litter nearly year-round. This is a normal condition.

Most varieties will not have fruit ready for harvest this early. However, other varieties are almost ready for picking. Varieties like ‘Gwen’ and ‘Whitsell’ often have fruit at unusual times.

Be sure to keep a very thick blanket of mulch, compost, or fallen leaves under mature avocados at all times. Avocados need a cool root-run for good health.

For more information, watch & learn: Edible Gardening: How to Grow Avocados in Southern California with Sarah Smith



Subtropical Fruits:

Subtropical fruit trees are all growing well now.

If you didn’t last month, fertilize now with a general-purpose organic fertilizer. Most tropicals and sub-tropicals have a higher need for trace minerals like iron, zinc, manganese, and others. Organic fertilizers generally contain lots of these trace minerals and work especially well in the warm soil temperatures present now.

June is a good month to plant these heat-loving fruit trees, but make sure to add regular watering to your gardening checklist to help them establish.

Watering should be frequent now, but most tropicals and sub-tropicals are particular about quick soil drainage.



Perennials:

June gardening tips for perennials are mostly focused on maintenance, though there’s still some time for planting perennial flowers. If you are planting perennials this month, be sure to keep them well-watered as these young plants head into the warm summer months. Try to avoid overgrown or root-bound plants, as they will be harder to establish.

Keep fertilizing your perennial plants. The frequency and amount will depend upon the formulation that you are using. If you have been building up your soil health, your fertilizing duties will be greatly reduced.

Removing the many spent or old flowers regularly will help them to produce more new flowers. Add the deadheaded blossoms to your compost bin.

Irrigating your perennials now is more important than it was just a month ago. The heat of summer is approaching, and there are no rains to help you out. Your perennials will respond well to careful irrigations now.

Subtropical perennials are at their happiest now and over the next two or three months. This is a good month to plant these heat lovers, too.

For more information, watch & learn: Gardening 101 Series | How to Use Annuals vs. Perennials with Lynn Hillman & Gardening 101 Series | Pruning Lavender & Perennials with Dalia Brunner



Clematis:

Many clematises are still blooming. Keep them well-fed with a balanced organic fertilizer to keep them going.

Clematis prefer cool roots, especially during the summer months. If you can, grow another shrub directly to the south of your clematis to provide some shade over the roots. Alternatively, place a large modern outdoor planter on the south side of the plant.

To insulate the roots even more and moderate the warm summer soil temperatures, maintain a thick 3-4 inch layer of organic mulch over the roots at all times, especially now.

As the weather warms up, apply more frequent irrigations.

If you are growing a spring-only flowering variety (not as common in Orange County), these should be pruned soon after their spring bloom is finished, which may be this month.



California Native Plants:

Be very cautious irrigating most of our California native perennials during the summer. Most of these are adapted to a “winter wet/summer dry” moisture cycle. Excessive irrigations now (especially in soils with a clay content) will certainly cause problems.

For more information, watch & learn: California Native Plants for Your Garden with James Maxwell, Success with Native Plants with James Maxwell, and All About Our Native Milkweed



Fuchsias:

Your fuchsia plants should still be in full bloom now.

Keep fertilizing regularly with a balanced fertilizer, or one slightly higher in phosphorus, to promote blooms.

Keep the plants well-watered, especially during a warm spell, and pay special attention to any plants in hanging baskets.

During any particularly dry, hot, and windy periods, misting the foliage a couple of times is very beneficial. If the soil is already moist from an early morning watering, be careful not to soak the soil again, or you may encourage root diseases.

Groom the plant periodically by removing dead flowers and any developing seed pods.

Watch for Fuchsia Gall Mites again this month. These nearly invisible pests are a serious threat to fuchsias. Look for any signs of puckered or distorted new growth. If you discover any, pinch it out and dispose of it immediately. A pesticide treatment is usually required.



Groundcovers:

Cool-season groundcovers are showing heat stress, especially in warm inland gardens and on south-facing slopes. Keep them irrigated and mulched.

Warm-season groundcovers are growing and blooming. Keep them irrigated as the weather warms.

If not already done, mulch most groundcover areas now to reduce weed growth, cool the roots, improve soil quality, and reduce summer irrigations.

For more information, watch & learn How to Plant & Grow Groundcover with Dalia Brunner



Bulbs, Rhizomes, Tubers, etc.:

Spring bulbs are long-finished flowering by now, but several warm-weather varieties are putting on a good show now in Orange County. These include some alliums, calla (in cool and moist situations), galtonia (summer hyacinth), gladiolus, hippeastrum, many true lilies, tigridia (recommended), tritelleia (recommended), and Watsonia.

Caladiums are continuing to sprout and grow nicely now. Keep them watered and fertilized and in bright but indirect light with shelter from winds.

Now that the soil is very warm, it is still a good time to plant tuberose tubers that you bought at the nursery in January or February or from those you dug out of your garden last November. Give them a sunny site and slightly acid, well-drained soil.

As spring bulbs finish blooming, do not hurry to cut back the foliage or ignore the plant. Keep the leaves in place and continue watering until the leaves naturally turn brown and dry, then you can cut them off. These leaves are sending energy to the bulb for next season.

For one-year bulbs (like most anemone, crocus, hyacinth, muscari, ranunculus, and tulips), after they are done blooming, you can pull them and toss them out.

For more information, view Gardening 101 Series | How Do I Plant Spring Bulbs?



Bearded Iris:

Bearded irises should have finished their first bloom by now.

Trim off the faded flower stalk just above the foliage when the last flower fades.

If you are growing any of the new “repeat-blooming” varieties, they may cycle again in as little as another month or two. Keep feeding these re-bloomers aggressively. Older “once-blooming” varieties can have their feeding reduced in half. Any fertilizer labeled for roses (but not with insecticides or other added ingredients) will do fine.



Dahlias (Tuberous Types):

Dahlia plants should be in full bloom, robust, and vigorous now.

Regularly cut off spent blooms to make the plants both look better and set more flowers.

Keep the taller varieties carefully staked to prevent the heavy canes from toppling over. Heavy natural cane bamboo stakes work well.

Dahlia perennials need water regularly and deeply, especially as they grow larger and the weather warms. Flooding the soil works best; overhead watering will cause broken stems and mushy flowers. Missed waterings now will cause gaps in the flower development later in the season.

Fertilize them regularly throughout their growing and blooming period. Use a liquid or granular organic fertilizer that is low in nitrogen and high in phosphorus. Fish bone meal is excellent.

For more information, watch & learn Lew Whitney's Secrets to Growing and Maintaining Dahlias



Cannas:

Cannas should be flowering well now.

Keep them well watered; cannas do not like dry soil.

As cannas flower, you may notice that each stalk produces a cluster of flowers at the top. After this cluster finishes, the stalk grows a few more inches and produces another cluster. In some varieties, this can go on for four or five clusters and last almost two months from beginning to end. When the last cluster of flowers has finished, cut the entire stalk to the soil. This stalk will never bloom again, and cutting it down will encourage more stalks and flowers to grow. Keep this process up all summer for the best results.



Tuberous Begonias:

Plants are still growing and should have buds and maybe even some flowers. Some gardeners pinch out the first set or two of flowers to focus more energy on the growth of the plant.

Most tuberous begonias produce both male (single) and female (double) flowers separately on the same plant. The double flowers are much showier, and many people pinch off the single (male) flowers as they appear.

Keep fertilizing regularly. Tuberous begonias are heavy feeders, especially in containers. Use a well-balanced fertilizer and periodically mix in an acid fertilizer to keep the soil pH low.

Keep them well-watered but not soggy. The soil should be rich and well-drained. The surface of the soil should dry slightly between watering.

If in a breezy location, staking upright varieties with a small bamboo stake will reduce the possibility of breakage.

Pinch off faded flowers regularly and rotate container-grown plants to ensure even growth.

If powdery mildew appears, treat it by improving air circulation around the plants. Usually, this will correct the problem; if not, use a fungicide.

For more information, watch & learn: Specialty Begonias with Sarah Smith



Tropicals & Subtropicals:

Tropical and subtropical plants are all growing well now, although many will not be in bloom yet. Don’t worry; they’re just waiting for longer days, even warmer daytime temperatures and especially warmer nights.

If you didn’t last month, fertilize now with a general-purpose organic fertilizer. Most tropicals and sub-tropicals have a higher need for trace minerals like iron, zinc, manganese, and others. Organic fertilizers generally contain lots of these trace minerals and work especially well in the warm soil temperatures present now.

This is a very good time to plant or transplant palms and cycads.

This is a good month for planting these heat lovers, but keep them well watered to help them establish.

Watering should be frequent now, but most tropicals and sub-tropicals are particular about quick soil drainage.



Ferns:

Ferns are pretty happy for now; you just need to make sure you keep them well-watered. You still have a bit of time to plant, re-pot, or transplant ferns, but be quick.

Hurry, but there is still time to re-mount and/or divide staghorn ferns that have outgrown their boards or outdoor pottery planters

Continue fertilizing your ferns. Use a mild, organic fertilizer on ferns and alternate periodically with an acid type, especially in high pH soil. For most common varieties, try blood meal alternated every third feeding with a cottonseed meal.

Irrigate most varieties regularly according to weather and the growth of the individual plants. Delicate fern varieties appreciate an occasional misting of the foliage, especially during warm, dry, or windy periods.

Keep checking for pests. Scale can be a problem and often goes undetected. It is often associated with ants, which need to be controlled as a part of any treatment program. On other ferns, especially staghorns, check carefully for early signs of spider mites.



Vegetables and Herbs

June is the time to get those warm-season veggies in the ground, and it’s not too late to plant herbs before the heat really kicks off. Those Mediterranean herbs that love summer heat should be happy in pots outside all summer. Here’s your June gardening checklist for the veggie and herb garden.

Vegetables:

Almost any warm-season vegetable can be planted now. Plant beans, chard, cucumbers, eggplants, lima beans, okra, peppers, squash, and tomatoes from transplants or seeds. Corn, melons, pumpkin, and sunflowers are best planted from seed.

Beets, carrots, chard, radish, and possibly turnips can be planted just about year-round. All but chard are planted from seed only. Be extra diligent about keeping the small seeds watered in this hot weather.

Along the immediate coast, gardeners can cheat a bit and still grow cool-season crops like arugula, lettuce, and some members of the cabbage family. June is the best month for these coastal gardeners to attempt real heat-lovers like corn, melons, peppers, and pumpkins. Grow them in the hottest spot in the garden, such as in front of a hot, light-colored, south-facing wall.

June is also a good month for planting the real heat lovers like corn, eggplant, jicama, lima beans, melons, okra, peppers, and pumpkins, now that the soil and night temperatures have warmed.

Plant pumpkin seeds for Halloween fruit. July 4 is the latest reliable date that seed can be started for a successful Halloween harvest. If you’re growing the “giant” types, it may already be too late.

Keep tomato plants trained inside their cages or, alternatively, up stakes or obelisks.

Time is running out to plant melons from seed. Get them in the ground or containers this month.

If growing corn, be sure to keep it continually fertilized and well-watered. Lapses in either will result in a poor yield.

Don’t worry if the first several squash flowers don’t set fruit. They’re male flowers.

Put in successive plantings of many vegetables a couple of weeks apart to ensure a constant, uninterrupted supply for the kitchen.

Keep planting corn from seed this month. Because corn needs to be cross-pollinated, it must be grown in clumps or rows. Twelve plants are about the minimum for good pollination, and twenty or more is even better. Plant crops successively every three to four weeks for a continual harvest. If planted in small groups, hand-pollinating will provide fuller ears.

Since most annual vegetables are shallow-rooted and quick growing, feed them regularly with a well-balanced organic fertilizer.

Keep the vegetable garden well-watered during the hot summer.

If you planted bulbing onions last fall, June is the ideal month for harvesting.



Herbs:

This is still a good time to plant basil. Be sure to pinch the flowers off of basil and many other herbs as they develop. Flowers not only reduce the quantity and size of the foliage but often change the flavor as well.

There’s still time to plant the annual summer savory! The perennial winter savory can also be planted now; however, the flavor of the perennial version is usually considered inferior.

Many perennial herbs can be kept in outdoor planted containers nearly year-round, but particularly during the warm summer. These include marjoram, oregano, rosemary, sage, thyme, catmint, catnip, chamomile, comfrey, feverfew, lavender, lemon balm, lemongrass, lemon verbena, St. John's wort, tansy, tarragon, and thyme.

General Gardening Info

Most of your general June garden maintenance checklist consists of keeping your garden watered and fertilizing regularly. Consistent watering starting now through the hottest part of the summer is the key to helping your plants thrive through the heat. Here are some general June gardening tips to look out for this month.



Beneficial Insects:

Beneficial insects should be abundant in your garden now, especially if you planted a few flowers just for them.

If needed, ladybugs and lacewings can be released again this month.

The population of natural predators and parasites always follows behind that of the pests. They will need some time to catch up with the pests, so be patient.

Giant whitefly is active again, and infestations should be noticeable. Predators and parasites should also be present by now. Check immature whiteflies carefully for signs of parasite activity. If none are found in one part of the garden, remove a few leaves from another plant that has been parasitized and place it carefully into the foliage of the non-parasitized plant.

Flea, grub, and cutworm populations may be present now. Control can be achieved by using various beneficial nematodes. These microscopic worms are applied by mixing them in a watering can, drenching the area, then watering well.

Encourage opossums, which are predators of the common garden snail.

Now that the weather has warmed, spider mites can become problems on many plants, such as citrus, avocado, pine, juniper, ivy, and others. Release beneficial predator mites now for control.

Trichogramma wasps are very effective parasites of caterpillars. If these pests are usually a problem in your garden, a couple of releases of these beneficials will be worthwhile. Space releases 30 to 45 days apart.



Lawns:

If you haven’t already, you still have time to de-thatch and aerate lawns like hybrid bermudagrass and St. Augustine.

Remember, cool-season lawns (fescue/marathon, ryegrass, bluegrass) should be mowed about half an inch higher in the warm months than in the cool months. Keep the mower at this higher setting for the next several hot weather months.

It’s too late to attempt to plant new cool-season lawns from seed. You can still try installing sod, but the risk of disease or dehydration is much higher in the warm weather.

This is still a good month to plant warm-season lawns (hybrid bermudagrass, St. Augustine, etc.) from sod. Most warm-season grasses do not grow from seed and are best only installed from sod.

Continue feeding warm-season lawns through summer and into fall.

Begin reducing the dosage of fertilizer by half in June for cool-season lawns. Too much fertilizer during the warm weather will make these cool-season turfs very susceptible to diseases.



Soil Care:

A thick layer of organic mulch, averaging about two inches, should be maintained on top of the soil just about year-round. Especially with the warm temperature of summer just ahead, this is an excellent time to refresh this layer and add additional mulch as needed.

Applied now, a thick layer of mulch will cool the root systems from the hot temperatures, reduce irrigations by as much as 50% this summer, reduce weed problems, and improve both soil life and soil quality.

We do not suggest the use of very high-analysis fertilizers in a garden, especially phosphorus.

Examples of fertilizers to avoid are synthetic versions with formulations like 10-55-10, 10-30-10, etc. We don’t even suggest the popular 15-30-15 formula. These formulations will inhibit or even destroy much of the soil life that is so vital to healthy, sustainable soil.

We also suggest that you not use soil-applied systemic fertilizer/insecticide combinations (especially popular with roses). These are very damaging to soil life.

Use insecticides only when necessary, and even then, use the least damaging product available. Many of these products move into the soil and interfere with the invisible soil life.

If you can, begin a compost pile or purchase a compost bin. Leaves, clippings, kitchen produce scraps, and many other ingredients can be composted and returned to the garden. Home compost is one of the very best ingredients you can add to your soil. The benefits are huge in the areas of disease suppression, increasing beneficial microorganisms, improving soil structure and texture, nutrient retention, and nematode suppression.

Be sure that, before you put a plant into the ground, you have considered the soil and are doing all you can to improve it and protect its health.

For more information, watch & learn:


How to Prepare Your Soil with Suzanne Hetrick
Gardening 101 Series | What Kind of Soil Should You Use?



Water & Irrigation:

Adjust the interval and duration of irrigations now as we head into the warmer months.

Periodically, rinse off the foliage of the plants in your garden during the summer. Larger shrubs, vines, and trees will need a spray from a garden hose. This will cleanse the foliage of dust and some pollution. Pest problems will be reduced, and the plants will “breathe” easier as well.

For more information, watch & learn: Gardening 101 Series | How to Water Baskets & Pots? with Dalia Brunner & CA Friendly Solutions | How to Install & Use High Efficiency Sprinkler Heads with David Rizzo & CA Friendly Gardening Solutions | Testing Your Sprinkler System with Tracy Wankner



Fertilizer:

Look for signs of chlorosis and apply appropriate fertilizer to correct the problem.

For more information, watch & learn: Why Fertilize & What do the Numbers Mean with Suzanne Hetrick & Fertilizer Tips 1- 2-3 with Suzanne Hetrick

Image Source: https://www.linkedin.com/company/los-angeles-county-arboretum-and-botanic-garden/



Places to Visit:

Gardens that look terrific almost any time of the year include Sherman Library and Gardens (Corona del Mar), The Fullerton Arboretum (Fullerton), Los Angeles Arboretum (Arcadia), Huntington Library and Botanical Gardens (San Marino), and San Diego Botanical Gardens (Encinitas).

Rose Hills Memorial Park (Whittier) is still in full bloom. This is not only a national All America Rose Selections trial garden; it is one of the top rose gardens on the west coast!

The last of the big home garden tours are wrapping up this month.

San Diego County Fair, held in Del Mar for three weeks from mid-June to early July, offers probably the best garden and horticulture presentations of any fair in California. Extensive landscaped displays, dozens of flower and landscape competitions, seminars, and much more make it well worth the visit.



Records, Catalogs, Books, and Organizations:

Summer is one of the best times to attend educational garden seminars and meetings. Many excellent programs are available, and most, but not all, are free with no memberships or reservations required. There is so much going on right now that you will have to pay close attention to keep track of it all!

Make notes in your journal now, especially about water and pests. These will be useful to you again next year.