Bloom · Berry
Below is a simple ‘shortlist’ of plants that are normally in bloom this month or are of interest for fruit, bark or foliage. See Bloom • Berry for comprehensive lists with links to photos and cultural information.
|Crape myrtle||Trumpet creeper|
Remember to change direction when moving your lawn. Travel north to south on one mowing and east to west on the next cutting.
- Mow often enough so that no more than ⅓ of the grass height is cut, and leave grass clippings on the lawn. Clippings decompose quickly and can provide up to 25% of the lawn’s fertilizer. If grass clippings are too plentiful, collect and use them as mulch or let them dry a bit and add to your compost pile.
- Mow fescue lawns to 3–3.5″.
- Mow Bermudagrass when the lawn first turns green using a reel mower set at ¾–1″ or a rotary mower set as low as possible without scalping.
If you have a fescue or bluegrass lawn, you can start preparing it now for reseeding in September.
Hopefully, you have read our LAWNS page and properly prepared your cool-season lawn for the heat and drought that is normal in our area. The page contains detailed watering instructions, which differ depending on whether you are keeping your lawn green or encouraging dormancy.
Use preventive measures for blackspot, powdery mildew, cankers, rust and botrytis on roses. Rugosa and Lady Banks roses are generally immune to disease. See the Earthkind trials for other genetically resistant, but not necessarily immune, cultivars. Currently, all roses are considered susceptible to rose rosette, so monitor for symptoms (especially on Knockout® roses) and carefully remove infected plants.
Do not fertilize woody plants. Fertilization now stimulates new growth that will not harden off properly in the fall and will make your tree or shrub more likely to suffer frost/freeze damage.
Beneficial insects share the same plants as insect pests. Use low-toxicity pesticides when possible, spray only if needed, and spray at dusk when the bees have all gone home. Always read and follow label directions for safe pesticide application.
- Aphids can attack tender new plant growth. They can be washed off with a forceful stream of water. Severe infestations can be controlled with the relatively environmentally benign insecticidal soaps.
- Lace bugs also can attack new growth, usually only on azalea and rhododendron, but sometimes on pyracantha, cotoneaster, quince or hawthorne. Dark spots about the size of a pinhead on the lower leaf surface are diagnostic. The best defense is to plant genetically resistant varieties and to maintain plant vigor. For control of severe infestations where there is no evidence that natural predators are present, repeated applications of insecticidal soap or horticultural oil can be effective. When a history of lace bug infestation exists, insecticides can be applied to the lower leaf surface, usually 2 applications ~2 weeks apart. Monitor the plants about once a month for reinfestations.
- Fall webworms are often mistaken for Eastern tent caterpillars, but do no lasting harm to trees. Tent caterpillars are active only in spring, while webworms become active beginning in mid-summer. Treatment is not necessary, but you can open the web to expose the caterpillars to predators.
- Slugs can attack soft new growth. Holes in leaves or on leaf margins and a silvery slime trail in the morning indicate slug damage. Slugs hide under boards, stones or debris during the day, so populations can be reduced by managing habitat. See the link for additional suggestions.
- Japanese beetles vary in numbers from year to year. Control by any method is difficult to achieve unless it covers a significant area. This requires careful monitoring and the coordinated effort of an entire neighborhood. A recommended alternative is to keep plants healthy (weak plants are more susceptible), to remove beetle attractants such as prematurely ripened or diseased fruit, and to plant resistant species. See the link for details on beetle lifecycle, monitoring, control, and species susceptibility.
- Kudzu bugs are a new pest from India and China that look somewhat like an olive lady beetle. They feed on all types of legumes (note that wisteria is a legume) and congregate on figs, magnolias, bronze fennel, redbuds, roses and peppers. Because they are so new, control strategies are still experimental. Carefully brushing them into soapy water is one approach (they release an irritant when crushed). Some predatory insects like assassin bugs and predatory stink bugs appear to be finding them, which may help to control population size. NC CES has additional information.
- Flatid planthoppers look like mealy bugs at first glance, but they usually do little damage and do not require treatment.
- Monitor for pests:
Plant Pest evergreens bagworms
remove bags by hand — sprays cannot penetrate them
spider mites azalea
Cut off the faded flowers of annuals, phlox, shasta daisy and daylily to encourage a second flowering (or for annuals, continual bloom). If annuals are spindly or leggy, trim them back by as much as ½ their current height to rejuvenate.
In a sunny location the temperature at the soil surface can be higher than the air temperature and bare soil will rapidly dry out. Mulch plants to a depth of about 3”, keeping it away from plant crowns, to conserve moisture and suppress weeds.
- This is still a great time to take semi-hardwood cuttings of azaleas, holly, rhododendron and many other shrubs.
- You can divide and transplant bearded iris.
- While you can safely divide or transplant many daylilies now, some cultivars rot when divided or transplanted in hot, humid conditions. The problem is not well understood. It is safer to propagate daylilies in mid to late September.
- Start cool-weather annual seeds indoors for for fall planting. Try foxglove, pansy, alyssum, snapdragons, ornamental cabbage (kale) and primroses. Pansy seeds germinate well when stored in the refrigerator (not freezer) for 10–14 days before planting.
- Sow perennial seeds of hollyhock, delphinium and stokesia outdoors to produce healthy plants for next spring. Lay the finished flower stalks of foxglove on the ground where you want new plants to grow or sprinkle the seeds from the dried pods.
- Plant lycoris (spider lily), colchicum (autumn crocus) and sternbergia bulbs.
Prune “bleeder” trees like maple, dogwood, birch and elm this month. You can prune off water sprouts by gentle rubbing. Prune off spent crape myrtle blossoms to prolong the flowering period, but only prune branches with a diameter less than that of a pencil.
Do not prune shrubs. Pruning now stimulates new growth that will not harden off properly in the fall and will make your shrub more likely to suffer frost/freeze damage.
Watch for root suckers on grafted roses and remove them promptly. These represent the rootstock species and not the hybrid you purchased. Suckers are usually very vigorous and can steal all of the resources from the top graft. They often have foliage that is distinctly different from the top graft.
- Manage vines such as trumpet creeper, blackberry and poison ivy, and remove “weed” or unwanted trees from your landscape.
- Weed in bed areas either by spraying or by hand. If hand-weeding, it is easier when the soil is damp. Try to get to weeds before they seed — if not your weed problems will multiply rapidly.
If drought threatens, set priorities. Trees come first, followed by shrubs, then perennials.
- Drought stress occurs when water lost through plant leaves exceeds either the water available to the plant in the soil or the water the plant is able to absorb via normal physiological processes. Warm summer breezes increase plant water loss. Most plants need 1–1.25” of water per week.
- Hard downpours can run off without soaking in, so plants can need watering even after a 3” rainfall.
- Clay soils absorb water at only ~ ¼” per hour, so soaker hoses are a great way to water. For large areas or lawns, cycle sprinklers on and off so that water has a chance to soak in and reach the roots: water for 15 minutes, turn off to let water soak in, water again for 15 minutes, turn off, etc.
- Water deeply to soak the soil 4–6” deep.
- Avoid wetting plant foliage. The best time to water is late night–early morning, which minimizes evaporation and ensures that if foliage is wetted, it dries quickly. This minimizes conditions that favor fungal disease.
- For trees, water around the drip line and as far as 3x the drip line — in clay soils, even tap-rooted trees, usually spread their roots widely and shallowly.
- Transplant broccoli, cabbage and cauliflower plants in mid-August.
- Plant beets, Chinese cabbage, cucumber, kale, kohlrabi, lettuce, mustard, radish, rutabaga, spinach, squash and turnip.
Pests · Disease
|Vegetable · herb||Monitor for:|
|Broccoli, cabbage, cauliflower||worms|
Avoid blossom end rot by keeping soil consistently moist and not over-fertilizing.
|Basil||downy mildew Leaves will look yellow and spores will be visible on the undersurface of the leaf. Flavored basils, such as lemon or cinnamon, are less susceptible. If you confirm infestation, you can report your findings to Cornell Universtiy.|
- Harvest vegetables early in the morning when water content is highest. This ensures the best flavor and texture.
- The tricky matter of when to harvest garlic
- Harvest Irish potatoes.
Vegetables need at least 1” of water each week to remain productive. In sandy soils apply 1/3” of water every third day to keep the top 6–8” of soil moist. In clay soils, water once or twice a week. Water early in the morning. Watering late in the day encourages disease.
- Pinch back basil, catmint, catnip and lemon basil to prevent flowering and keep them bushy, but allow some basil plants to bloom to attract bees. Sow a new crop each month to harvest leaves.
- Each time you need a few chives from the garden, cut generously to encourage new growth. Snip the extras into short segment, put them in a plastic container and store in the freezer.
- Swallowtail butterfly larvae (caterpillars) love fennel, parsley, dill, rue, and composite flowers like Queen Anne's Lace. Plant extras so that both you and the caterpillars can enjoy them. Add some joe-pye weed to feed the butterflies once they appear.
- Spray your tree fruits and bunch grapes on a regular basis. Spray peach and nectarine trunks for peach tree borers at the end of August.
Prune out dieback.
- Blackberries · raspberries
Prune the fruiting canes of raspberry and blackberry plants after harvest is over. Cut canes at ground level.
This winter caused significant damage to figs. If you are lucky enough to have fruits, harvest them when they soften and turn downward. Otherwise, prune out dead material and consider protecting trees next winter with 1–2 feet of loose mulch such as leaves or straw. Do NOT fertilize — in our area, fertilization makes figs more susceptible to cold damage.
Floppy baptisias? Disappointing heucheras? Disappearing echinacea? Mildewed monarda? See which cultivars perform best in the Piedmont. The Mt. Cuba center is also beginning trials to determine which plants provide the most nutritional pollen and nectar for pollinators.
- Feed hummingbirds!
- Most plants with tube-shaped flowers will attract hummingbirds. Note that cultivated hybrids often make much less nectar than wild strains.
- Hummingbirds become abundant at feeders beginning in mid-July. Fill feeders with a solution of 1 part sugar in 4 parts water. Boil for 2–4 minutes to dissolve all sugar, then cool. Wash feeders and replace the food at least twice weekly.
- Attend to birdbaths. Change water frequently to keep it fresh and prevent mosquitoes from breeding. Scrub your bath to keep it clean and remove mold that can make it slippery for birds. Birds prefer water that is no more than 2 inches deep.
Lawn · Garden Moisture IndexColors indicate inches of precipitation deficit/excess with a resolution of 4km.
This live feed maps the difference between recent garden-effective precipitation and the amount normally adequate for the time of year. Soil water-holding capacity is not considered, but the index still provides a good idea of current soil moisture.Check drought conditions