September Gardening Checklist
September Gardening Checklist
By Ron Vanderhoff - Nursery Manager
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.
(See also Sweet Peas and Wildflowers)
This is still really a month for warm-season annuals. The nights are still warm, the days are still rather long and sunny, and the temperatures are high. Along the immediate coast cool-season flowers can start going in this month. For other gardeners this is a bit risky as 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 quick 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 color, plant garden mums.
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. This is the last possible month to try to still get an avocado 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 avocadoes at all times. Avocadoes need a cool root-run for good health.
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 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. This is another good month to leach the salts out of the root zone of your plants. This is done by irrigating the plant over and over again or by flooding the root basin several times to wash any accumulated salt below and away from the roots.
This is another good month to dig, transplant and divide these. In fact, 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 (by not with insecticides or other added ingredients) will do fine. This is the last good month to plant new bearded iris.
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. Control can be achieved by using various beneficial nematodes. These microscopic worms are applied by mixing them in a water 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 and others. Release beneficial predator mites now for control.
Bulbs, rhizomes, tubers, etc:
(See also Bearded Iris, Dahlias, Cannas and Tuberous Begonias)
When 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). Purchase spring blooming bulbs now. This is the season in southern California when the greatest variety of flower bulbs are available. Bulbs available to purchase now 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. Mediterranean varieties can be planted now or all the way 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, but prior to the foliage beginning to grow again this fall. Only perform this chore if it is absolutely necessary since crowded conditions provide better flowering. This is a good time to dig, divide and re-plant many of the bulbs that naturalize in Orange County gardens. Those to at least consider dividing now include babiana, chasmanthe, some crocus, some daffodils and narcissus, Dutch Iris, gladiolus, hippeastrum and leucojum. Some of these varieties perform best when allowed to go undisturbed for many years, while others need division and re-planting regularly. Check with a knowledgeable source before you begin.
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 frequent irrigations now (especially in soils with a clay content) will certainly cause problems.
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 general 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 general 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. This is another good month to leach the salts out of the root zone of your plants. This is done by irrigating the plant over and over again or by flooding the root basin several times to wash any accumulated salt below and away from the roots.
If you have been pruning out the bloomed out stalks, as mentioned again below, they should still be flowering well now. 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. Keep this process up all summer for the best results.
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 a 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 Dr. Earth. Keep ants out of your citrus at all times. If they are crawling up the trunk of the tree apply Tanglefoot (a sticky, waterproof substance) to stop them. Be especially attentive to irrigation in the warm weather. 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.
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 the plant 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 irrigation.
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 E-Rase.
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 be producing now.
Continue irrigating most varieties regularly according to the weather. Delicate varieties 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.
(See also the information under the individual plants)
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.
Your plants may be looking a bit stressed now, especially because of the long hot months. Keep feeding them with a balanced 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 in the evening and check the soil moisture most every day. Never let the soil dry out completely. During a particularly dry, hot or a Santa Ana wind a couple of mistings of the foliage is very beneficial. Groom the plant periodically by removing dead flowers and any developing seedpods. The chances of infestations of Fuchsia Gall Mites are about over for this year. Take one more look on the new foliage for any signs of puckered or distorted growth. If you discover any, pinch it out and dispose of it immediately.
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 acidic formula to keep the pH down. If the leaves are showing 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. This is another good month to leach the salts out of the root zone of your plants. This is done by irrigating the plant over and over again or by flooding the root basin several times to wash any accumulated salt below and away from the 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.
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 may be look bit heat stressed. Keep up with removing spent flowers regularly to encourage more bloom. Martha types have finished blooming for this year.
Continue fertilizing all geraniums, except most scented types, regularly with a balanced fertilizer. Geraniums prefer a slightly acidic soil, so periodically alternate feedings with an acid type, such as Cottonseed Meal. 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 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 BT on a regular basis.
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 usually about now. Depending upon the variety, continue harvesting fruit when it is fully formed and well colored. If birds or wildlife are a problem, protect the plants with nearly invisible black nylon 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.
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. Cool season groundcover 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.
This 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 seed now, as they know their life is almost over. This is a good time to get the herb garden ready for the big planting season next month. Soil preparation now will give you a head start.
If you haven’t pruned your hydrangeas yet, it is almost too late. Do it as soon as possible. If not, don’t do any pruning until next summer or you will eliminate most of your flowers. Remember to only prune down the flowering stems that had flowers this summer. Do not prune the unflowered stems; these will produce next years blooms.
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 apply 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 if you are in a cooler coastal garden you can cheat a bit and start now. 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 kikuyugrass 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 it 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 that will potentially ensure an even larger problem next year. For small problems water the lawn and then hand pull the clumps – they will remove fairly easily in the soggy soil. For larger infestations use a selective herbicide with the ingredient “MSMA”. Follow label directions carefully.
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 a 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.
Some grasses are now developing seed heads, although many are still a month or more away. These seed heads can be quite ornamental and are one of the most ornamental aspects of these plants. A few grasses may want to re-seed either in your garden or even into an adjacent wild area. If this as an issue, prune these seed heads off before the heads are fully ripe to prevent the seeds from dispersing.
(See also Bearded Iris, Bulbs/Rhizomes/Tubers, Cannas, Dahlias, Fuchsias, Geraniums, Ornamental Grasses and Tuberous Begonias)
This is the beginning of the big fall planting season for perennials. Planting now allows these plants to establish themselves all fall and winter, for a great spring bloom. As you shop for these plants, they will not be coming into bloom, but going out of bloom. Experienced gardeners know not to worry about this and they install most of their perennials and shrubs over the next couple of months. Most perennials will get their last regular fertilizing this month, especially in mild coastal gardens. This is a great time to dig and divide many common garden perennials that have become a bit too big for their space. Other perennials benefit from a periodic division and re-planting, which tends to re-invigorate them and stimulates new growth and flowers for next year. Examples are agapanthus, lily turf, campanula, calla, daylily, rudbeckia, Shasta daisy and yarrow. Removing spent or old flowers regularly will help them to produce more new flowers. Some of these 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 insure spring blooms.
Pests & Diseases:
(See also the information under the individual plants and Beneficial Insects)
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.
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 Quail Botanical Gardens (Encinitas).
Planting: (See also the information under the individual plants)
Do not pinch or prune the plant.Reduce fertilizing to half strength. Watch for whiteflies and treat as needed. Protect the plant from high winds to avoid breaking the stems. Keep the plants well watered.
Records, Catalogs, Books and Organizations:
Since next month is the big planting month in Orange County, start making notes in your journal now about what needs to be done. Three separate lists can very useful: 1) what to remove, 2) what to plant – your shopping list, 3) what to divide, cut back or prune and 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 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 are applicable to our very unique gardening climate here in Orange County.
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 the months of October and November. If you did a “summer pruning” last month your plants will be looking especially healthy and will have lots of new growth and buds. Disease should not be much of an issue now, except along the immediate coast. Do not use soil-applied fertilizers combined with 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. Rather than use fertilizer/insecticide combinations (which severely disrupt soil life), 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 as well.
Shrubs: (See also the information under Azaleas, Camellias, Gardenias, Hydrangeas and others)
We have included this section, because as you know, or will discover with more experience, a good garden begins with the soil. Investing in the soil, managing the soil and protecting the soil are not afterthoughts in a successful garden, but the foundation. Healthy soil is living and breathing, teaming with earthworms, microorganisms, beneficial fungi, bacteria, microbes and other invisible life. This section, possibly the most important topic of all will, provides some helpful guidance to good 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 irrigation as much as half this summer, reduce weed growth, 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 a 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.
If strawberries keep attempting to grow runners, keep pinching them off. A few fruit may still be produced. Keep checking regularly.
(See also the information under Avocados, and Citrus)
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 and others. Organic fertilizers generally contain lots of these trace minerals and work especially well in the warm soil temperatures present now. It’s getting late for any significant planting. Watering should still be fairly frequent, depending on the temperatures.
This the important beginning of the Sweet Pea season. Shop for seeds now. Seeds will be in good supply now. This is an especially good time to plant seeds of early-blooming (also called “short-day”) varieties that may bloom by Christmas. These varieties include ‘Winter Elegance’ (our favorite) and ‘Early Multiflora’.
(See also the information under Avocados, Citrus, Deciduous Fruit Trees and Subtropical Fruits)
Deep water as needed according to the tree species, its age and the weather. A light pruning at this time may help the trees deal with the strong Santa Ana winds.
Tropicals & Subtropicals:
(See also the information under Avocados, Citrus and 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 and others. Organic fertilizers generally contain lots of these trace minerals and work especially 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 bit late for any significant planting of these heat lovers, better to wait until late next spring or early summer. Watering should still be fairly frequent, depending on the temperatures.
Plants should still be blooming well. Keep fertilizing. Use a well balanced 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 a fungicide.
Toward the end of the month cool-season vegetables can start going in. 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. From seed plant beets, carrots, favas, parsnip, radishes, rutabaga and turnips. Beets, carrots, chard, radish and possibly turnips can be planted just about year-round. All but chard are planted from seed only. Although most should still be growing well, it 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 certain that varieties are chosen properly for our climate. Putting in successive plantings of many vegetables a couple of weeks apart from each other will insure a constant, uninterrupted supply for the kitchen. Cut asparagus to the ground after the tops turn yellow/brown. If strawberries attempt to grow runners, pinch them off. Keep feeding them and they will continue to bear fruit. Check tomato plants for hornworm caterpillars. Hand pick 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.
Water & Irrigation:
(See also the information under the individual plants)
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 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.
It is still too early to be thinking about wildflower seeding. However, if you want to get a head start on weed control in the area 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 a non residual herbicide like Roundup. Repeat the process once or twice more before the wildflowers are scattered, in about November. You will then have far less weed seed germination.
On established plants, your second pruning of the year should have been last month. No need to prune now. You’ll do you final pruning in December. Established wisterias need only an occasional deep summer watering and little, if any, fertilizer. However, iron is occasionally needed 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 it to encourage quick coverage and deep roots. It is not unusual to have some random summer and fall flowers, especially if you are following the pruning instructions given here. Enjoy them.
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