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September 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 four 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. There’s plenty to do in the garden in September to get ready for fall, so don’t delay getting started. Gardening is sharing your tips, tricks, and knowledge. Any corrections, comments, or suggestions are appreciated and will improve future information.

Table of Contents:




Annuals:

● September is a month for warm-season annual plants. The nights are still warm, the days are still relatively long and sunny, and the temperatures are still high. But, it’s also time to start thinking about the coming cool season. You can plant a few different annuals in September; here’s what you need to know:

● Along the immediate coast, cool-season flowers can start to be planted in September. This is a bit risky for other gardeners in other areas as the temperature can still be quite warm in these areas.

● Keep newly planted annuals well-watered until they are thoroughly rooted; You can still get at least a couple of months of color out of dahlias, zinnias, lisianthus, petunias, lobelia, verbena, marigold, ageratum, cosmos, gomphrena, salvia, portulaca, impatiens, and begonias.

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

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

● For instant fall color, you can plant garden mums in September.

Geraniums:

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

● Ivy and zonal types are still blooming but might look a bit heat-stressed.

● Keep up with removing spent flowers regularly to encourage more blooms.

● Martha types have finished blooming for this year.

● Continue fertilizing all geraniums, except most scented types, regularly with a balanced fertilizer. Geraniums prefer slightly acidic soil, so periodically alternate feedings with an organic acid type fertilizer, such as Cottonseed Meal.

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

● This is another good time to take healthy three to four-inch tip cuttings to propagate all varieties. For best results, use sterile shears, let the cutting “cure” for a few hours in a dry shady area, and root them in clean potting soil and clean pots. When thoroughly rooted, plant them into the garden to replace old, tired, and woody plants.

● Budworms may still be attacking the developing buds and new leaves. If necessary, spray with organic BT insecticide regularly.

Sweet Peas:

● This is the critical beginning of the Sweet Pea season. Shop for seeds now as they will be in good supply.

● Sweet peas need as much sun as possible but also need to be kept relatively moist until they germinate about seven days after planting. Plant these flowers in a sunny location, with something to climb, and then make sure to keep them well watered while they get started.

● September is one of the best times to plant seeds of early-blooming (also called “short-day”) varieties that may bloom by Christmas (with a little luck). These varieties include ‘Winter Elegance’ (our favorite) and ‘Early Multiflora.’

● Start planting your sweet pea flowers in the garden in late September, and keep planting successive batches every week through the month, so you’ll have sweet pea blooms as long as possible through winter and spring.

● Learn more by watching: ● World Class Sweet Peas with Steve Hampson

Wildflowers:

● It is still too early to be thinking about wildflower seeding. However, if you want to get a head-start on weed control, try this: Irrigate the area lightly, but several times a day. This will germinate many of the weed seeds after a couple of weeks. Once they germinate, either control them with a very shallow Hula-Hoe (also called a “Wiggle Hoe”) or spray with an organic weed control product.

● Repeat the process once or twice more before the wildflowers are scattered, in about November. You will then have far less weed seed germination.



● Fruiting Plants

● Grapes are one of the main fruits in season during September, so harvest and enjoy them.

Strawberries:

● If strawberries keep attempting to grow runners, continue pinching them off.

● Strawberries should be slowing down now, but keep looking for the odd last berry.

● A few fruits may still be produced. Keep checking regularly.

● Learn more by watching: ● How to Grow the Best Strawberries with Sarah Smith

Grapes:

● Assuming the use of a granular organic product, the feeding of grapes is in six to eight-week intervals following the first application, which was applied when the new growth was just emerging. Following this schedule, four applications are usually sufficient. The final application is about now.

● Depending upon the variety, continue harvesting grapes when the fruit is fully-formed and well-colored.

● If birds or wildlife are a problem, protect the plants with nearly invisible black nylon fruit netting.

● Continue irrigating regularly and deeply in the warm summer temperatures.

● Watch for signs of powdery mildew on the foliage. Usually, this is due to poor air circulation around the plant, too much shading, or the lack of a winter dormant spray. If treatment now is necessary, use an organic Neem oil product.

Shrubs:

● September is when many shrubs are starting to slow down and feel the heat stress. It’s important now to keep them well irrigated to mitigate the stress and get them through until the weather cools off and they can relax for a season. (CA native plants are an exception to this rule.)

● September is an excellent month to leach the salts out of the root zone of your shrubs, trees, or perennials. This is done by repeatedly irrigating the plant or flooding the root basin several times to wash any accumulated salt below and away from the roots.

● Learn more by watching: ● Hardy Flowering Shrubs with Dalia Brunner

Azaleas:

● Continue to keep azaleas well irrigated in the warm summer weather.

● In the ground, only two feedings per year are necessary. Your first feeding was in late spring, at the end of their bloom period. This is your only other feeding of the year. Use a light application of an organic acid fertilizer, like Cottonseed Meal.

● Do not cultivate the soil. Azaleas are shallow-rooted and dry out quickly. Avoid cultivating or allowing other plants to grow under or in competition with the roots of your azalea.

Camellias:

● Continue to keep camellias well irrigated in the warm weather of this month and next. If camellias dry out too much now, they often will not show much stress. However, this is a significant cause of bud drop in their February – March bloom period.

● Japanese camellias are about done with their “growth” cycle for the year and are now setting flower buds for next spring.

● No need to apply any fertilizer to camellias until after their blooms have finished next year.

● Sasanqua camellias are done with their “growth” cycle for the year and do not need any fertilizer until after their bloom period has finished next year.

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

● Learn more by watching: ● Gardening 101 Series | How to Plant & Maintain a Camellia

Gardenias:

● Many gardenias will still be blooming.

● Give them one more feeding now. Use a fertilizer with trace minerals, such as most organic types, and alternate this with an organic acidic formula to keep the pH down.

● If the leaves show signs of green veins with yellow areas between the veins, especially on the new growth, they need additional iron. Iron is a supplement to the regular fertilizing program of your gardenia.

● Gardenias are shallow-rooted and will dry out quickly. Avoid cultivating or allowing other plants to grow under or in competition with their roots.

● Gardenias do not like hot, dry winds. If these threaten, do what you can to shield the plant.

● A light misting and syringe of the leaves also helps.

● Learn more by watching: ● How to Successfully Grow Gardenias with Sarah Smith

Hydrangeas:

● If you haven’t pruned your hydrangeas yet, it is almost too late, unless you are growing the new repeat-blooming varieties. Do any pruning as soon as possible. If not, don’t do any pruning until next summer, or you will eliminate most of your flowers on old-wood varieties.

● Remember only to prune the stems that had flowers this summer. Do not prune the unflowered stems; these will produce next year’s blooms. This does not apply if you are growing the new repeat-blooming varieties.

● Learn more by watching: ● Blooming Hydrangeas with Sarah Smith

Roses:

● The heat of summer has taken a toll on roses, especially in inland gardens. However, many modern varieties of roses are coming into their “second spring” in southern California.

● Buds will be developing now for a strong bloom during October and November.

● If you did a “summer pruning” last month, your plants will look especially healthy and have lots of new growth and buds.

● Disease should not be much of an issue now, except perhaps along the immediate coast.

● 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.

● Continue regular fertilizing. Use a well-balanced organic product.

● Keep deadheading roses as they fade.

● Stay on the lookout for pests. Rose slug problems are about over for this year, but spider mites like the warm, dry summer temperatures.

● Irrigations should be frequent and deep in the warm summer weather.

● Hose off the foliage of roses frequently. Not only does this cool and clean the plants, but it discourages spider mites and mildew as well.

● Learn more by watching: ● Our Rose Playlist

Wisterias:

● On established plants, your second pruning of the year should have been last month—no need to prune now. You’ll do your final pruning in December.

● Established wisterias need only an occasional deep summer watering and little, if any, fertilizer. However, iron is occasionally required to correct chlorosis.

● 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.

● It is not unusual to have some random summer and fall flowers, especially if you follow the pruning instructions given here. Enjoy them!

Fruit:

● September brings some late summer tree care tasks for the gardener. Water your trees deeply as needed, according to the tree species, their age, and the weather. As your trees finish fruiting, it is a good idea to give them a light pruning, which can help protect them from strong Santa Ana winds and can help control the size of the tree. Here are a few more summer tree care tips to get you through September.

Deciduous Fruit Trees:

● Continue monitoring soil moisture and irrigating as needed. Remember, to limit the size of your trees, the correct time to prune them is immediately following fruit harvest, which may be as late as now.

● Most peaches, nectarines, apricots, and plums are finished producing fruit by now. However, many apple and pear varieties are still producing fruit.

Citrus:

● Valencia oranges should still be ripe now. Valencias will keep on the tree for months with no loss of flavor, so only pick what you need at the time.

● Your trees should still look pretty good this month, although their new growth will have already slowed down considerably.

● For plants in the ground, feeding is finished for this year.

● Potted citrus should continue being fed with a ½ to 1/3 dose application through the fall. Use an organic fertilizer that is rich in such trace minerals as iron, zinc, manganese, copper, and others. These ingredients are usually well represented in organic fertilizers like Down to Earth.

● Keep ants out of your citrus at all times. If they crawl up the tree trunk, apply Tanglefoot (a sticky, waterproof substance) to stop them.

● Be especially attentive to irrigations in the warm weather. The best application method is 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.

● Learn more by watching: ● Our Citrus Playlist

Avocados:

● 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.

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

● Timing tip: September is the last possible month if you care to still get a new avocado tree planted this year. Being sub-tropical plants, avocados prefer to be planted during the long warm part of the year.

● Some mid-season fruiting varieties, like ‘Mexicola,’ may have fruit ready to harvest. Remember that avocado fruit does not ripen on the tree; it must be removed and should ripen indoors at room temperature.

● Be sure to keep a very thick blanket of mulch, compost, or fallen leaves under mature avocado trees at all times, especially in the summer. Avocados need a cool root-run for good health.

● Learn more by watching: ● Edible Gardening: How to Grow Avocados in Southern California with Sarah Smith

Subtropical Fruits:

● This will probably be your last full feeding with a general-purpose organic fertilizer. Most tropicals and sub-tropicals have a higher need for trace minerals like iron, zinc, manganese, etc. Organic fertilizers generally contain many trace minerals and work incredibly well in the warm soil temperatures present now.

● It’s getting late for any significant planting.

● Watering should still be pretty frequent, depending on the temperatures.

Perennials:

September is the beginning of the big fall planting season for both flowering and non-flowering perennials.

● Planting now allows perennials to establish themselves all fall and winter for great spring blooming.

● As you shop for these plants in September, they will not be coming into bloom, but going out of bloom. Experienced gardeners know not to worry about this, and they get most of their perennials and shrubs planted over the next couple of months.

● Most perennials, except California natives, will get their last regular fertilizing this month, especially in mild coastal gardens.

● September is a great time to dig and divide many common clumping garden perennials that have become a bit too big for their space.

● Many perennials benefit from a periodic division and replanting, which tends to re-invigorate them and stimulates new growth and flowers for next year. Examples are agapanthus, lilyturf, campanula, calla, daylily, rudbeckia, Shasta daisy, and yarrow.

● Removing spent or old flowers regularly will help them to produce more new flowers. Some of which can be dried and used in the home for fall arrangements.

● Some perennials are actually biennials (two-year plants) or at least behave like biennials in our climate. For loads of spring flowers, set out transplants this month and next. These include Canterbury bells (Campanula medium), hollyhock (Alcea), Queen Anne’s lace (Ammi majus), most foxglove (Digitalis), and most delphiniums. Don’t wait until next spring, which most beginners will do; these must be fall-planted to ensure spring blooms.

● Learn more by watching: Gardening 101 Series | How to Use Annuals vs. Perennials with Lynn Hillman

Cannas:

● If you have been pruning out the finished bloomed stalks, as mentioned below, canna’s will be one of the few perennial plants that should still be flowering well into autumn.

● Cannas are one of the longest blooming plants in a garden.

● Continue to keep them well-watered in the hot summer weather; 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.

Clematis:

● Many clematis offer a heavy second bloom spike during the late summer or fall. Yours may be beginning this bloom cycle now.

● Apply a half-strength feeding to these early fall-blooming flowers now.

● To keep the roots cool, maintain a thick 3-4 inch layer of organic mulch over them at all times, especially now.

● In the warm summer weather, be sure to apply more frequent irrigations.

Poinsettias:

● Do not pinch or prune the plant.

● Reduce fertilizing to half strength.

● Watch for whiteflies and treat them as needed.

● Protect the plant from high winds to avoid breaking the stems.

● Keep the plants well-watered.

California Native Plants:

● Be very cautious irrigating most of our native plants during the summer. Most of these are adapted to a winter wet – summer dry moisture cycle. Too many frequent irrigations now (especially in soils with a clay content), will undoubtedly cause problems.

● Next month begins the best planting season for natives. Start planning now or place your special orders, so that you won’t miss out.

● Calscape (Calscape.org) is a great tool and resource for native plant gardeners.

Learn More by Watching: ● California Native Plants for Your Garden with James Maxwell

● California Native Plants with Sarah Smith

● All About Our Native Milkweed

Fuchsias:

● Your plants may be looking a bit stressed now, primarily because of the long, hot months.

● Keep feeding them with a balanced organic fertilizer or one slightly higher in phosphorus to try to get a few more flowers.

● Proper watering is still critical at this time of the year, especially for those plants in hanging baskets. Water early in the morning or the evening and check the soil moisture almost every day. Never let the soil dry out completely.

● During a particularly dry, hot Santa Ana wind, misting the foliage is very beneficial.

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

● The chances of infestations of Fuchsia Gall Mites are about over for this year. Take one more look at the new foliage for any signs of puckered or distorted growth. If you discover any, pinch it out and dispose of it immediately.

● Learn more by reading: Fuchsia Gardening Success

Groundcovers

● Many warm-season groundcovers are still blooming, but soon they will be slowing down and preparing for cool weather. Fertilize lightly, if at all, and only do light pruning, as needed, no heavy cutting-back now.

● Conversely, cool-season groundcovers will be waking up shortly and beginning to grow and even bloom well.

● Continue to irrigate carefully. Periods of very hot, dry weather can dry out groundcover areas quickly.

● Learn more by watching: ● How to Plant & Grow Groundcover with Dalia Brunner

Orchids

● On cymbidiums, switch now to a higher phosphorus fertilizer through the bloom period, which should be in winter or earliest spring.

● It may be possible to move your potted cymbidiums to a bit more light now. The foliage should be slightly bleached out lime-green. If it is a deep “healthy” green, there is a good chance that it is in too much shade and in a few months may bloom poorly.

● Learn more by watching: ● Our Video Playlist about Orchids

Bulbs, rhizomes, tubers, etc.:

● Even in September, there are blooming bulbs in Orange County. These include amaryllis belladonna (finishing up), colchicum, eucomis (pineapple lily), lycoris (spider lily), tuberose, and urginia (giant squill).

● Fall is the season in southern California when the greatest variety of flower bulbs are available, including perennials. Bulbs available to purchase in September include such favorites as ranunculus, freesia, anemone, Dutch iris, daffodil, tulip, watsonia, sparaxis, chasmanthe, lily, babiana, and many others. These dormant bulbs, rhizomes, tubers, and corms arrive at nurseries during the second half of the month.

● Some of these can be planted right away, but many should be stored for a month or two. It is too early to plant your true cold weather/Dutch favorites like tulips, daffodils, hyacinth, spring-blooming crocus, allium, and lilies.

● You can plant Mediterranean varieties now or through November or December, including ranunculus, freesia, anemone, Dutch iris, watsonia, chasmanthe, and babiana.

● This is perhaps the best time to plant most South African native bulbs. Most of these are naturally adapted to a wet winter and dry summer. Some of these include babiana, freesia, homeria, ixia, nerine, sparaxis, tritonia, and watsonia.

● Amaryllis belladonna, commonly called “Naked Ladies,” can be dug and divided now if necessary – but hurry. The best time to do this is after the flowers have finished, and isn’t absolutely necessary since crowded conditions provide better flowering.

● September is an excellent time to dig, divide, and replant many bulbs that naturalize in Orange County gardens. At the very least, consider dividing babiana, chasmanthe, some crocus, daffodils and narcissus, Dutch Iris, gladiolus, hippeastrum, and leucojum.

● Some of these varieties perform best when undisturbed for many years, while others need division and replanting regularly. Check with a knowledgeable source before you begin.

● Learn more by watching: ● Fall Planted Bulbs for Southern California Gardens with Sarah Smith

Bearded Iris:

● September is another good month to dig, transplant, and divide bearded irises. This is the final really good month to do this and still have a good likelihood of blooms next spring.

● Bearded iris should be dug and divided about every four years (every two or three years for aggressive re-blooming varieties).

● If you are growing any of the new “repeat-blooming” varieties, they will often bloom again now or next month. Keep feeding these re-bloomers aggressively.

● Older “once-blooming” varieties can have their feeding reduced in half. Any organic fertilizer labeled for roses (not with insecticides or other added ingredients) will do fine.

Dahlias (tuberous types):

● Plants should still be blooming well and enjoying the warm weather.

● 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.

● Water regularly and deeply throughout the summer months. Flooding the soil works best; overhead watering will cause broken stems and mushy flowers.

● Continue fertilizing regularly. Use a liquid or granular organic fertilizer that is low in nitrogen and high in phosphorus. Fish Bone Meal is excellent.

● If powdery mildew appears on the lower leaves, use organic Neem oil or Rose Defense.

● Learn More by watching: ● How to Grow & Maintain Dahlias with Steve Hampson● + ● Lew Whitney's Secrets to Growing and Maintaining Dahlias● + ● How to Plant Dahlias with Sarah Smith● + ● All About Cafe Au Lait Dahlias with Sarah Smith

Tuberous Begonias:

● Plants should still be blooming well.

● Keep fertilizing. Use a well-balanced organic fertilizer, periodically alternated with an acid fertilizer.

● Keep them well-watered but not soggy, especially during hot periods.

● Keep pinching off faded flowers regularly.

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

● Learn more by watching: ● Specialty Begonias with Sarah Smith

Tropicals & Subtropicals:

● This will probably be your last full feeding with a general-purpose organic fertilizer. Most tropicals and sub-tropicals have a higher need for trace minerals like iron, zinc, manganese, etc. Organic fertilizers generally contain many trace minerals and work incredibly well in the warm soil temperatures present now.

● Most of these should now be in bloom. However, in some cool coastal gardens, some varieties might not bloom at all or may just be beginning.

● It is getting a bit late for any significant planting of these heat-lovers, better to wait until late next spring or early summer.

● Watering should still be pretty frequent, depending on the temperatures.

● Foliage Plants

● In September, taking care of foliage plants includes regular irrigation and staying alert for weed seeds,if you don’t want them to spread.

Ferns:

● Continue irrigating most varieties regularly according to the weather. Delicate types appreciate an occasional misting of the foliage, especially during warm, dry, or windy periods.

● This is the last feeding of the year necessary for most varieties. Use a mild, organic fertilizer.

● Keep checking for pests. On many ferns, especially staghorns, spider mites are a summer pest and often go undetected until the problem gets out of hand.

Ornamental Grasses

● Some grasses are now developing seed heads, although many are still a month or more away. These seed heads are one of the most ornamental aspects of these plants.

● A few types of grass may want to re-seed either in your garden or even into an adjacent wild area. If this is an issue, prune these seed heads off before the heads are fully ripe to prevent the seeds from dispersing.

● Learn more by watching: ● Using Grasses to Soften Your Garden with Sarah Smith● + ● Low Water Ornamental Grasses with James Maxwell

Vegetables & Herbs:

We’re heading towards the shift from warm-season gardening to cool-season again. There are plenty of garden chores and planting for September, but the effort will be all worth it for the tasty homegrown produce you’ll have all winter.

Vegetables

● Toward the end of September, you can start to grow cool-season vegetables. Plant transplants or seeds of arugula, broccoli, Brussels sprouts, cabbage, cauliflower, celery, collards, endive, kale, lettuce, kohlrabi, mesclun mix, mustard, onions, parsley, peas, and spinach.

● Sow seed for beets, carrots, favas, parsnip, radishes, rutabaga, and turnips. You can plant beets, carrots, chard, radish, and possibly turnips just about year-round. All but chard are grown from seed only.

● Although most should still be growing well, September is too late to consider planting more warm-season vegetables. Early maturing varieties of bush beans may be the only exception.

● If planting garlic, onions, shallots, or leeks from sets (little bulbs), wait until the end of the month and be sure that varieties are appropriately chosen for our climate.

● Putting in successive plantings of many veggies a couple of weeks apart from each other, starting in September, will ensure a constant, uninterrupted supply for the kitchen.

● Cut asparagus to the ground after the tops turn yellow/brown.

● Check tomato plants for hornworm caterpillars. Handpick them or use the safe and organic BT spray.

● 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 hot weather.

● Learn more by watching: ● Fall Vegetables and Raised Beds with David Rizzo● + ● Edible Gardening Series Cool Season Vegetable Gardening with Suzanne Hetrick● + ● The Best Vegetables to Grow in the Cool Fall Season with Sarah Smith● + ● How to Plant Cool Season Tomatoes

Herbs:

● September is the first month to consider planting cool-season herbs. Next month is a little safer, but coastal gardeners can take a chance now.

● While many of your perennial herbs will grow all winter, many do not. Basil (except African blue basil) is beginning to struggle in the shorter days and cooler nights.

● Do your best to continue pinching out the flower buds to preserve the flavor and continue getting some foliage. This will be a task because the plants want desperately to set flowers and seeds now, as they know their life is almost over.

● This is an excellent time to get the herb garden ready for the big planting season next month. Soil preparation now will give you a head start.

● Learn more by watching:

● Unique and Unusual Herb Plants with Sarah Smith



General Gardening Info

September is a busy month for garden and lawn care. Be vigilant in checking for pests and weeds this month as both bugs and weeds seem to be busier than ever in September. If you stay on top of the weeds in your lawn before it gets out of control, it will be much easier to maintain. There are plenty of organic options for dealing with garden pests, so don’t reach insecticide just yet, check out the suggestions below first.

Beneficial Insects:

● Giant Whitefly infestations will still be noticeable. Predators and parasites should be helping to control the problem. As with all prey/predator relationships, the prey (in this case, the Giant Whitefly) is never completely eliminated. Instead, its population is reduced to a tolerable level.

● Flea, grub, and cutworm populations may still be doing damage now. You can achieve control by using various beneficial nematodes. These microscopic worms are applied by mixing them in a watering can and drenching the area, then watering well. In September’s warm weather, spider mites will be noticed on many plants, such as citrus, avocado, pine, juniper, ivy, etc. Release beneficial predator mites now for control.

Pests & Diseases:

● Watch for cabbage worms on cole crops. Snails and slugs. Periodically rinsing off the foliage of the plants in your garden during the summer will significantly reduce many pest problems, especially mites and whitefly.

● Learn more by watching: How to Identify & Eliminate Common Garden Pests

Lawns:

● Toward the first of the month on the coast and the end of the month inland, apply pre-emergent weed control to prevent Poa Annua (annual bluegrass) from germinating. You will use it again about Jan. 1.

● Keep mowing cool-season lawns (fescue/Marathon, ryegrass, bluegrass) about a half an inch higher during this last really warm month.

● It’s still a little warm to attempt to plant new cool-season lawns, but you can cheat a bit and start now if you are in a cooler coastal garden.

● Continue feeding warm-season lawns to keep them green and growing. This is the last month to reduce the dosage of fertilizer by half to cool-season lawns. Too much fertilizer during the warm weather will make these cool-season turfs susceptible to various diseases.

● This is the last really good month to plant warm-season lawns (hybrid bermudagrass, St. Augustine, etc.) from sod; just keep them well-watered. Most warm-season grasses do not grow from seed and are best only installed from sod.

● If your cool-season grass has been infested with warm-season turfs like bermudagrass or Kikuyu grass, this is the best month of the year to control it. A selective herbicide, named “Grass Getter,” can be sprayed over your cool-season lawn, and it will suppress warm-season grasses without damaging the cool-season grasses.

● Crabgrass is at its growing peak now, and the clumps will be easy to notice in lawns. It will also be setting seed either now or in the next month or two. For minor problems, water the lawn and then hand pull the clumps – they will remove pretty easily in the soggy soil; for larger infestations, use a selective herbicide with the ingredient “MSMA.” Follow label directions carefully.

● 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 ● Quail Botanical Gardens● (Encinitas).

Records, Catalogs, Books, and Organizations:

● Since next month is the big planting month in Orange County, start making notes in your journal about what needs to be done. Three separate lists can be very useful:

● 1) What to remove

● 2) What to plant – your shopping list

● 3) What to divide, cut back, or prune

● 4) What to find out more about. This last list is one of the most important and includes plants that you want to learn more about, garden techniques, questions for the nursery staff, etc.

● If you don’t already have it, buy Robert Smaus’s book “52 weeks in the California Garden.” Written in a month-by-month format, beginning in September, and specifically for southern California gardens. This is one of the best, most accurate gardening books ever written and is required reading for any avid gardener. Many mail-order plant and seed companies send out “fall” catalogs about now; check the mail for these. They can be a lot of fun and also educational. Be careful, however, that the plants and information apply to our very unique gardening climate here in Orange County.

Fertilizer:

● Do not feed frost-sensitive or sub-tropical plants this time of year.

● Feed new annuals and vegetables that have been planted recently as cool-season crops.

Learn more by watching:
Fertilizer Tips 1- 2-3 with Suzanne Hetrick
Why Fertilize & What do the Numbers Mean with Suzanne Hetrick

Soil Care:

● A thick layer of organic mulch, averaging about two inches, should be maintained on top of the soil just about year-round. Add additional mulch as needed to maintain this level. Applied now, a thick layer of mulch will cool the root systems from hot summer temperatures, reduce irrigations by as much as half, reduce weed growth, and improve 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, 15-30-15, etc.. These formulations will inhibit or even destroy much of the soil life 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 enormous in 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.

Learn more by watching: How to Prepare Your Soil with Suzanne Hetrick

Water & Irrigation:

● Watch out for drying Santa Ana winds. Take down hanging baskets and set them on the ground when these winds blow. Periodically, rinse off the foliage of the plants in your garden during the summer. Larger shrubs, vines, and trees will need spray from a garden hose. This will cleanse the foliage of dust and some pollution. You will reduce pest problems, and the plants will “breathe” easier as well.

Learn more by watching: Gardening 101 Series | How to Water Baskets & Pots? with Dalia Brunner

QUICK LINKS:
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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:

● September is a month for warm-season annual plants. The nights are still warm, the days are still relatively long and sunny, and the temperatures are still high. But, it’s also time to start thinking about the coming cool season. You can plant a few different annuals in September; here’s what you need to know:

● Along the immediate coast, cool-season flowers can start to be planted in September. This is a bit risky for other gardeners in other areas as the temperature can still be quite warm in these areas.

● Keep newly planted annuals well-watered until they are thoroughly rooted; You can still get at least a couple of months of color out of dahlias, zinnias, lisianthus, petunias, lobelia, verbena, marigold, ageratum, cosmos, gomphrena, salvia, portulaca, impatiens, and begonias.

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

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

● For instant fall color, you can plant garden mums in September.

Geraniums:

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

● Ivy and zonal types are still blooming but might look a bit heat-stressed.

● Keep up with removing spent flowers regularly to encourage more blooms.

● Martha types have finished blooming for this year.

● Continue fertilizing all geraniums, except most scented types, regularly with a balanced fertilizer. Geraniums prefer slightly acidic soil, so periodically alternate feedings with an organic acid type fertilizer, such as Cottonseed Meal.

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

● This is another good time to take healthy three to four-inch tip cuttings to propagate all varieties. For best results, use sterile shears, let the cutting “cure” for a few hours in a dry shady area, and root them in clean potting soil and clean pots. When thoroughly rooted, plant them into the garden to replace old, tired, and woody plants.

● Budworms may still be attacking the developing buds and new leaves. If necessary, spray with organic BT insecticide regularly.

Sweet Peas:

● This is the critical beginning of the Sweet Pea season. Shop for seeds now as they will be in good supply.

● Sweet peas need as much sun as possible but also need to be kept relatively moist until they germinate about seven days after planting. Plant these flowers in a sunny location, with something to climb, and then make sure to keep them well watered while they get started.

● September is one of the best times to plant seeds of early-blooming (also called “short-day”) varieties that may bloom by Christmas (with a little luck). These varieties include ‘Winter Elegance’ (our favorite) and ‘Early Multiflora.’

● Start planting your sweet pea flowers in the garden in late September, and keep planting successive batches every week through the month, so you’ll have sweet pea blooms as long as possible through winter and spring.

● Learn more by watching: ● World Class Sweet Peas with Steve Hampson

Wildflowers:

● It is still too early to be thinking about wildflower seeding. However, if you want to get a head-start on weed control, try this: Irrigate the area lightly, but several times a day. This will germinate many of the weed seeds after a couple of weeks. Once they germinate, either control them with a very shallow Hula-Hoe (also called a “Wiggle Hoe”) or spray with an organic weed control product.

● Repeat the process once or twice more before the wildflowers are scattered, in about November. You will then have far less weed seed germination.



● Fruiting Plants

● Grapes are one of the main fruits in season during September, so harvest and enjoy them.

Strawberries:

● If strawberries keep attempting to grow runners, continue pinching them off.

● Strawberries should be slowing down now, but keep looking for the odd last berry.

● A few fruits may still be produced. Keep checking regularly.

● Learn more by watching: ● How to Grow the Best Strawberries with Sarah Smith

Grapes:

● Assuming the use of a granular organic product, the feeding of grapes is in six to eight-week intervals following the first application, which was applied when the new growth was just emerging. Following this schedule, four applications are usually sufficient. The final application is about now.

● Depending upon the variety, continue harvesting grapes when the fruit is fully-formed and well-colored.

● If birds or wildlife are a problem, protect the plants with nearly invisible black nylon fruit netting.

● Continue irrigating regularly and deeply in the warm summer temperatures.

● Watch for signs of powdery mildew on the foliage. Usually, this is due to poor air circulation around the plant, too much shading, or the lack of a winter dormant spray. If treatment now is necessary, use an organic Neem oil product.

Shrubs:

● September is when many shrubs are starting to slow down and feel the heat stress. It’s important now to keep them well irrigated to mitigate the stress and get them through until the weather cools off and they can relax for a season. (CA native plants are an exception to this rule.)

● September is an excellent month to leach the salts out of the root zone of your shrubs, trees, or perennials. This is done by repeatedly irrigating the plant or flooding the root basin several times to wash any accumulated salt below and away from the roots.

● Learn more by watching: ● Hardy Flowering Shrubs with Dalia Brunner

Azaleas:

● Continue to keep azaleas well irrigated in the warm summer weather.

● In the ground, only two feedings per year are necessary. Your first feeding was in late spring, at the end of their bloom period. This is your only other feeding of the year. Use a light application of an organic acid fertilizer, like Cottonseed Meal.

● Do not cultivate the soil. Azaleas are shallow-rooted and dry out quickly. Avoid cultivating or allowing other plants to grow under or in competition with the roots of your azalea.

Camellias:

● Continue to keep camellias well irrigated in the warm weather of this month and next. If camellias dry out too much now, they often will not show much stress. However, this is a significant cause of bud drop in their February – March bloom period.

● Japanese camellias are about done with their “growth” cycle for the year and are now setting flower buds for next spring.

● No need to apply any fertilizer to camellias until after their blooms have finished next year.

● Sasanqua camellias are done with their “growth” cycle for the year and do not need any fertilizer until after their bloom period has finished next year.

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

● Learn more by watching: ● Gardening 101 Series | How to Plant & Maintain a Camellia

Gardenias:

● Many gardenias will still be blooming.

● Give them one more feeding now. Use a fertilizer with trace minerals, such as most organic types, and alternate this with an organic acidic formula to keep the pH down.

● If the leaves show signs of green veins with yellow areas between the veins, especially on the new growth, they need additional iron. Iron is a supplement to the regular fertilizing program of your gardenia.

● Gardenias are shallow-rooted and will dry out quickly. Avoid cultivating or allowing other plants to grow under or in competition with their roots.

● Gardenias do not like hot, dry winds. If these threaten, do what you can to shield the plant.

● A light misting and syringe of the leaves also helps.

● Learn more by watching: ● How to Successfully Grow Gardenias with Sarah Smith

Hydrangeas:

● If you haven’t pruned your hydrangeas yet, it is almost too late, unless you are growing the new repeat-blooming varieties. Do any pruning as soon as possible. If not, don’t do any pruning until next summer, or you will eliminate most of your flowers on old-wood varieties.

● Remember only to prune the stems that had flowers this summer. Do not prune the unflowered stems; these will produce next year’s blooms. This does not apply if you are growing the new repeat-blooming varieties.

● Learn more by watching: ● Blooming Hydrangeas with Sarah Smith

Roses:

● The heat of summer has taken a toll on roses, especially in inland gardens. However, many modern varieties of roses are coming into their “second spring” in southern California.

● Buds will be developing now for a strong bloom during October and November.

● If you did a “summer pruning” last month, your plants will look especially healthy and have lots of new growth and buds.

● Disease should not be much of an issue now, except perhaps along the immediate coast.

● 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.

● Continue regular fertilizing. Use a well-balanced organic product.

● Keep deadheading roses as they fade.

● Stay on the lookout for pests. Rose slug problems are about over for this year, but spider mites like the warm, dry summer temperatures.

● Irrigations should be frequent and deep in the warm summer weather.

● Hose off the foliage of roses frequently. Not only does this cool and clean the plants, but it discourages spider mites and mildew as well.

● Learn more by watching: ● Our Rose Playlist

Wisterias:

● On established plants, your second pruning of the year should have been last month—no need to prune now. You’ll do your final pruning in December.

● Established wisterias need only an occasional deep summer watering and little, if any, fertilizer. However, iron is occasionally required to correct chlorosis.

● 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.

● It is not unusual to have some random summer and fall flowers, especially if you follow the pruning instructions given here. Enjoy them!

Fruit:

● September brings some late summer tree care tasks for the gardener. Water your trees deeply as needed, according to the tree species, their age, and the weather. As your trees finish fruiting, it is a good idea to give them a light pruning, which can help protect them from strong Santa Ana winds and can help control the size of the tree. Here are a few more summer tree care tips to get you through September.

Deciduous Fruit Trees:

● Continue monitoring soil moisture and irrigating as needed. Remember, to limit the size of your trees, the correct time to prune them is immediately following fruit harvest, which may be as late as now.

● Most peaches, nectarines, apricots, and plums are finished producing fruit by now. However, many apple and pear varieties are still producing fruit.

Citrus:

● Valencia oranges should still be ripe now. Valencias will keep on the tree for months with no loss of flavor, so only pick what you need at the time.

● Your trees should still look pretty good this month, although their new growth will have already slowed down considerably.

● For plants in the ground, feeding is finished for this year.

● Potted citrus should continue being fed with a ½ to 1/3 dose application through the fall. Use an organic fertilizer that is rich in such trace minerals as iron, zinc, manganese, copper, and others. These ingredients are usually well represented in organic fertilizers like Down to Earth.

● Keep ants out of your citrus at all times. If they crawl up the tree trunk, apply Tanglefoot (a sticky, waterproof substance) to stop them.

● Be especially attentive to irrigations in the warm weather. The best application method is 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.

● Learn more by watching: ● Our Citrus Playlist

Avocados:

● 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.

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

● Timing tip: September is the last possible month if you care to still get a new avocado tree planted this year. Being sub-tropical plants, avocados prefer to be planted during the long warm part of the year.

● Some mid-season fruiting varieties, like ‘Mexicola,’ may have fruit ready to harvest. Remember that avocado fruit does not ripen on the tree; it must be removed and should ripen indoors at room temperature.

● Be sure to keep a very thick blanket of mulch, compost, or fallen leaves under mature avocado trees at all times, especially in the summer. Avocados need a cool root-run for good health.

● Learn more by watching: ● Edible Gardening: How to Grow Avocados in Southern California with Sarah Smith

Subtropical Fruits:

● This will probably be your last full feeding with a general-purpose organic fertilizer. Most tropicals and sub-tropicals have a higher need for trace minerals like iron, zinc, manganese, etc. Organic fertilizers generally contain many trace minerals and work incredibly well in the warm soil temperatures present now.

● It’s getting late for any significant planting.

● Watering should still be pretty frequent, depending on the temperatures.

Perennials:

September is the beginning of the big fall planting season for both flowering and non-flowering perennials.

● Planting now allows perennials to establish themselves all fall and winter for great spring blooming.

● As you shop for these plants in September, they will not be coming into bloom, but going out of bloom. Experienced gardeners know not to worry about this, and they get most of their perennials and shrubs planted over the next couple of months.

● Most perennials, except California natives, will get their last regular fertilizing this month, especially in mild coastal gardens.

● September is a great time to dig and divide many common clumping garden perennials that have become a bit too big for their space.

● Many perennials benefit from a periodic division and replanting, which tends to re-invigorate them and stimulates new growth and flowers for next year. Examples are agapanthus, lilyturf, campanula, calla, daylily, rudbeckia, Shasta daisy, and yarrow.

● Removing spent or old flowers regularly will help them to produce more new flowers. Some of which can be dried and used in the home for fall arrangements.

● Some perennials are actually biennials (two-year plants) or at least behave like biennials in our climate. For loads of spring flowers, set out transplants this month and next. These include Canterbury bells (Campanula medium), hollyhock (Alcea), Queen Anne’s lace (Ammi majus), most foxglove (Digitalis), and most delphiniums. Don’t wait until next spring, which most beginners will do; these must be fall-planted to ensure spring blooms.

● Learn more by watching: Gardening 101 Series | How to Use Annuals vs. Perennials with Lynn Hillman

Cannas:

● If you have been pruning out the finished bloomed stalks, as mentioned below, canna’s will be one of the few perennial plants that should still be flowering well into autumn.

● Cannas are one of the longest blooming plants in a garden.

● Continue to keep them well-watered in the hot summer weather; 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.

Clematis:

● Many clematis offer a heavy second bloom spike during the late summer or fall. Yours may be beginning this bloom cycle now.

● Apply a half-strength feeding to these early fall-blooming flowers now.

● To keep the roots cool, maintain a thick 3-4 inch layer of organic mulch over them at all times, especially now.

● In the warm summer weather, be sure to apply more frequent irrigations.

Poinsettias:

● Do not pinch or prune the plant.

● Reduce fertilizing to half strength.

● Watch for whiteflies and treat them as needed.

● Protect the plant from high winds to avoid breaking the stems.

● Keep the plants well-watered.

California Native Plants:

● Be very cautious irrigating most of our native plants during the summer. Most of these are adapted to a winter wet – summer dry moisture cycle. Too many frequent irrigations now (especially in soils with a clay content), will undoubtedly cause problems.

● Next month begins the best planting season for natives. Start planning now or place your special orders, so that you won’t miss out.

● Calscape (Calscape.org) is a great tool and resource for native plant gardeners.

Learn More by Watching: ● California Native Plants for Your Garden with James Maxwell

● California Native Plants with Sarah Smith

● All About Our Native Milkweed

Fuchsias:

● Your plants may be looking a bit stressed now, primarily because of the long, hot months.

● Keep feeding them with a balanced organic fertilizer or one slightly higher in phosphorus to try to get a few more flowers.

● Proper watering is still critical at this time of the year, especially for those plants in hanging baskets. Water early in the morning or the evening and check the soil moisture almost every day. Never let the soil dry out completely.

● During a particularly dry, hot Santa Ana wind, misting the foliage is very beneficial.

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

● The chances of infestations of Fuchsia Gall Mites are about over for this year. Take one more look at the new foliage for any signs of puckered or distorted growth. If you discover any, pinch it out and dispose of it immediately.

● Learn more by reading: Fuchsia Gardening Success

Groundcovers

● Many warm-season groundcovers are still blooming, but soon they will be slowing down and preparing for cool weather. Fertilize lightly, if at all, and only do light pruning, as needed, no heavy cutting-back now.

● Conversely, cool-season groundcovers will be waking up shortly and beginning to grow and even bloom well.

● Continue to irrigate carefully. Periods of very hot, dry weather can dry out groundcover areas quickly.

● Learn more by watching: ● How to Plant & Grow Groundcover with Dalia Brunner

Orchids

● On cymbidiums, switch now to a higher phosphorus fertilizer through the bloom period, which should be in winter or earliest spring.

● It may be possible to move your potted cymbidiums to a bit more light now. The foliage should be slightly bleached out lime-green. If it is a deep “healthy” green, there is a good chance that it is in too much shade and in a few months may bloom poorly.

● Learn more by watching: ● Our Video Playlist about Orchids

Bulbs, rhizomes, tubers, etc.:

● Even in September, there are blooming bulbs in Orange County. These include amaryllis belladonna (finishing up), colchicum, eucomis (pineapple lily), lycoris (spider lily), tuberose, and urginia (giant squill).

● Fall is the season in southern California when the greatest variety of flower bulbs are available, including perennials. Bulbs available to purchase in September include such favorites as ranunculus, freesia, anemone, Dutch iris, daffodil, tulip, watsonia, sparaxis, chasmanthe, lily, babiana, and many others. These dormant bulbs, rhizomes, tubers, and corms arrive at nurseries during the second half of the month.

● Some of these can be planted right away, but many should be stored for a month or two. It is too early to plant your true cold weather/Dutch favorites like tulips, daffodils, hyacinth, spring-blooming crocus, allium, and lilies.

● You can plant Mediterranean varieties now or through November or December, including ranunculus, freesia, anemone, Dutch iris, watsonia, chasmanthe, and babiana.

● This is perhaps the best time to plant most South African native bulbs. Most of these are naturally adapted to a wet winter and dry summer. Some of these include babiana, freesia, homeria, ixia, nerine, sparaxis, tritonia, and watsonia.

● Amaryllis belladonna, commonly called “Naked Ladies,” can be dug and divided now if necessary – but hurry. The best time to do this is after the flowers have finished, and isn’t absolutely necessary since crowded conditions provide better flowering.

● September is an excellent time to dig, divide, and replant many bulbs that naturalize in Orange County gardens. At the very least, consider dividing babiana, chasmanthe, some crocus, daffodils and narcissus, Dutch Iris, gladiolus, hippeastrum, and leucojum.

● Some of these varieties perform best when undisturbed for many years, while others need division and replanting regularly. Check with a knowledgeable source before you begin.

● Learn more by watching: ● Fall Planted Bulbs for Southern California Gardens with Sarah Smith

Bearded Iris:

● September is another good month to dig, transplant, and divide bearded irises. This is the final really good month to do this and still have a good likelihood of blooms next spring.

● Bearded iris should be dug and divided about every four years (every two or three years for aggressive re-blooming varieties).

● If you are growing any of the new “repeat-blooming” varieties, they will often bloom again now or next month. Keep feeding these re-bloomers aggressively.

● Older “once-blooming” varieties can have their feeding reduced in half. Any organic fertilizer labeled for roses (not with insecticides or other added ingredients) will do fine.

Dahlias (tuberous types):

● Plants should still be blooming well and enjoying the warm weather.

● 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.

● Water regularly and deeply throughout the summer months. Flooding the soil works best; overhead watering will cause broken stems and mushy flowers.

● Continue fertilizing regularly. Use a liquid or granular organic fertilizer that is low in nitrogen and high in phosphorus. Fish Bone Meal is excellent.

● If powdery mildew appears on the lower leaves, use organic Neem oil or Rose Defense.

● Learn More by watching: ● How to Grow & Maintain Dahlias with Steve Hampson● + ● Lew Whitney's Secrets to Growing and Maintaining Dahlias● + ● How to Plant Dahlias with Sarah Smith● + ● All About Cafe Au Lait Dahlias with Sarah Smith

Tuberous Begonias:

● Plants should still be blooming well.

● Keep fertilizing. Use a well-balanced organic fertilizer, periodically alternated with an acid fertilizer.

● Keep them well-watered but not soggy, especially during hot periods.

● Keep pinching off faded flowers regularly.

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

● Learn more by watching: ● Specialty Begonias with Sarah Smith

Tropicals & Subtropicals:

● This will probably be your last full feeding with a general-purpose organic fertilizer. Most tropicals and sub-tropicals have a higher need for trace minerals like iron, zinc, manganese, etc. Organic fertilizers generally contain many trace minerals and work incredibly well in the warm soil temperatures present now.

● Most of these should now be in bloom. However, in some cool coastal gardens, some varieties might not bloom at all or may just be beginning.

● It is getting a bit late for any significant planting of these heat-lovers, better to wait until late next spring or early summer.

● Watering should still be pretty frequent, depending on the temperatures.

● Foliage Plants

● In September, taking care of foliage plants includes regular irrigation and staying alert for weed seeds,if you don’t want them to spread.

Ferns:

● Continue irrigating most varieties regularly according to the weather. Delicate types appreciate an occasional misting of the foliage, especially during warm, dry, or windy periods.

● This is the last feeding of the year necessary for most varieties. Use a mild, organic fertilizer.

● Keep checking for pests. On many ferns, especially staghorns, spider mites are a summer pest and often go undetected until the problem gets out of hand.

Ornamental Grasses

● Some grasses are now developing seed heads, although many are still a month or more away. These seed heads are one of the most ornamental aspects of these plants.

● A few types of grass may want to re-seed either in your garden or even into an adjacent wild area. If this is an issue, prune these seed heads off before the heads are fully ripe to prevent the seeds from dispersing.

● Learn more by watching: ● Using Grasses to Soften Your Garden with Sarah Smith● + ● Low Water Ornamental Grasses with James Maxwell

Vegetables & Herbs:

We’re heading towards the shift from warm-season gardening to cool-season again. There are plenty of garden chores and planting for September, but the effort will be all worth it for the tasty homegrown produce you’ll have all winter.

Vegetables

● Toward the end of September, you can start to grow cool-season vegetables. Plant transplants or seeds of arugula, broccoli, Brussels sprouts, cabbage, cauliflower, celery, collards, endive, kale, lettuce, kohlrabi, mesclun mix, mustard, onions, parsley, peas, and spinach.

● Sow seed for beets, carrots, favas, parsnip, radishes, rutabaga, and turnips. You can plant beets, carrots, chard, radish, and possibly turnips just about year-round. All but chard are grown from seed only.

● Although most should still be growing well, September is too late to consider planting more warm-season vegetables. Early maturing varieties of bush beans may be the only exception.

● If planting garlic, onions, shallots, or leeks from sets (little bulbs), wait until the end of the month and be sure that varieties are appropriately chosen for our climate.

● Putting in successive plantings of many veggies a couple of weeks apart from each other, starting in September, will ensure a constant, uninterrupted supply for the kitchen.

● Cut asparagus to the ground after the tops turn yellow/brown.

● Check tomato plants for hornworm caterpillars. Handpick them or use the safe and organic BT spray.

● 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 hot weather.

● Learn more by watching: ● Fall Vegetables and Raised Beds with David Rizzo● + ● Edible Gardening Series Cool Season Vegetable Gardening with Suzanne Hetrick● + ● The Best Vegetables to Grow in the Cool Fall Season with Sarah Smith● + ● How to Plant Cool Season Tomatoes

● September is the first month to consider planting cool-season herbs. Next month is a little safer, but coastal gardeners can take a chance now.

● While many of your perennial herbs will grow all winter, many do not. Basil (except African blue basil) is beginning to struggle in the shorter days and cooler nights.

● Do your best to continue pinching out the flower buds to preserve the flavor and continue getting some foliage. This will be a task because the plants want desperately to set flowers and seeds now, as they know their life is almost over.

● This is an excellent time to get the herb garden ready for the big planting season next month. Soil preparation now will give you a head start.

● Learn more by watching:

● Unique and Unusual Herb Plants with Sarah Smith



General Gardening Info

September is a busy month for garden and lawn care. Be vigilant in checking for pests and weeds this month as both bugs and weeds seem to be busier than ever in September. If you stay on top of the weeds in your lawn before it gets out of control, it will be much easier to maintain. There are plenty of organic options for dealing with garden pests, so don’t reach insecticide just yet, check out the suggestions below first.

Beneficial Insects:

● Giant Whitefly infestations will still be noticeable. Predators and parasites should be helping to control the problem. As with all prey/predator relationships, the prey (in this case, the Giant Whitefly) is never completely eliminated. Instead, its population is reduced to a tolerable level.

● Flea, grub, and cutworm populations may still be doing damage now. You can achieve control by using various beneficial nematodes. These microscopic worms are applied by mixing them in a watering can and drenching the area, then watering well. In September’s warm weather, spider mites will be noticed on many plants, such as citrus, avocado, pine, juniper, ivy, etc. Release beneficial predator mites now for control.

Pests & Diseases:

● Watch for cabbage worms on cole crops. Snails and slugs. Periodically rinsing off the foliage of the plants in your garden during the summer will significantly reduce many pest problems, especially mites and whitefly.

● Learn more by watching: How to Identify & Eliminate Common Garden Pests

Lawns:

● Toward the first of the month on the coast and the end of the month inland, apply pre-emergent weed control to prevent Poa Annua (annual bluegrass) from germinating. You will use it again about Jan. 1.

● Keep mowing cool-season lawns (fescue/Marathon, ryegrass, bluegrass) about a half an inch higher during this last really warm month.

● It’s still a little warm to attempt to plant new cool-season lawns, but you can cheat a bit and start now if you are in a cooler coastal garden.

● Continue feeding warm-season lawns to keep them green and growing. This is the last month to reduce the dosage of fertilizer by half to cool-season lawns. Too much fertilizer during the warm weather will make these cool-season turfs susceptible to various diseases.

● This is the last really good month to plant warm-season lawns (hybrid bermudagrass, St. Augustine, etc.) from sod; just keep them well-watered. Most warm-season grasses do not grow from seed and are best only installed from sod.

● If your cool-season grass has been infested with warm-season turfs like bermudagrass or Kikuyu grass, this is the best month of the year to control it. A selective herbicide, named “Grass Getter,” can be sprayed over your cool-season lawn, and it will suppress warm-season grasses without damaging the cool-season grasses.

● Crabgrass is at its growing peak now, and the clumps will be easy to notice in lawns. It will also be setting seed either now or in the next month or two. For minor problems, water the lawn and then hand pull the clumps – they will remove pretty easily in the soggy soil; for larger infestations, use a selective herbicide with the ingredient “MSMA.” Follow label directions carefully.

● 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 ● Quail Botanical Gardens● (Encinitas).

Records, Catalogs, Books, and Organizations:

● Since next month is the big planting month in Orange County, start making notes in your journal about what needs to be done. Three separate lists can be very useful:

● 1) What to remove

● 2) What to plant – your shopping list

● 3) What to divide, cut back, or prune

● 4) What to find out more about. This last list is one of the most important and includes plants that you want to learn more about, garden techniques, questions for the nursery staff, etc.

● If you don’t already have it, buy Robert Smaus’s book “52 weeks in the California Garden.” Written in a month-by-month format, beginning in September, and specifically for southern California gardens. This is one of the best, most accurate gardening books ever written and is required reading for any avid gardener. Many mail-order plant and seed companies send out “fall” catalogs about now; check the mail for these. They can be a lot of fun and also educational. Be careful, however, that the plants and information apply to our very unique gardening climate here in Orange County.

Fertilizer:

● Do not feed frost-sensitive or sub-tropical plants this time of year.

● Feed new annuals and vegetables that have been planted recently as cool-season crops.

Learn more by watching:
Fertilizer Tips 1- 2-3 with Suzanne Hetrick
Why Fertilize & What do the Numbers Mean with Suzanne Hetrick

Soil Care:

● A thick layer of organic mulch, averaging about two inches, should be maintained on top of the soil just about year-round. Add additional mulch as needed to maintain this level. Applied now, a thick layer of mulch will cool the root systems from hot summer temperatures, reduce irrigations by as much as half, reduce weed growth, and improve 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, 15-30-15, etc.. These formulations will inhibit or even destroy much of the soil life 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 enormous in 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.

Learn more by watching: How to Prepare Your Soil with Suzanne Hetrick

Water & Irrigation:

● Watch out for drying Santa Ana winds. Take down hanging baskets and set them on the ground when these winds blow. Periodically, rinse off the foliage of the plants in your garden during the summer. Larger shrubs, vines, and trees will need spray from a garden hose. This will cleanse the foliage of dust and some pollution. You will reduce pest problems, and the plants will “breathe” easier as well.

Learn more by watching: Gardening 101 Series | How to Water Baskets & Pots? with Dalia Brunner