Tidewater Gardening - August 2010


August is Maintenance Month
K. Marc Teffeau

For brighter blooms this fall, and a better flower garden next year, start now. The August gardening schedule includes feeding fall-blooming flowers, staking tall plants, dividing iris and day lilies and starting a compost pile.
Plants that bloom in the late summer and fall, such as chrysanthemums and asters, should be fertilized in July or August. Apply a general purpose liquid fertilizer according to label instructions. It’s too late to feed roses as the tender late summer growth that fertilizer encourages may not withstand the winter temperatures.
Some of those tall flowers in the garden may need a little support. Stake them with bamboo stakes or metal rods before the plants bend over. Fancier and more expensive metal stakes for tall flowers are also available from some of the more “upscale” gardening catalogs.
Dahlias, delphiniums and hollyhocks need support for the best flower display. Use strings or twisties to fasten the flowers to the support. I also like to use the plastic ties that electricians use to tie wires together. They are inexpensive and you can buy them in bulk. Tie the string tightly to the support, but loosely around the plant or stem. This is also the time to cut out the dead flower stalks.
Many plants in the flower border will make excellent house plants this winter. Among the plants that are easy to maintain indoors are begonias, coleus, geraniums and ivy. If they are already being grown in containers it is a simple matter to bring them indoors. Before you do that, however, clean up the pots, remove diseased and insect infested leaves and treat them with an insecticidal soap to prevent bringing and pests inside.
Start moving your plants in at night when the temperature drops below 60° so as to maintain their vigor and flower production. For optimum bloom, locate them where they receive sunlight equivalent to what they received outside. If you are planning to take some garden plants indoors to provide for early fall bloom, use a sharp knife to root prune them to a size a little smaller than the pot. Remove all buds and flowers and cut back the top growth severely.
Plant bulbs of the hardy amaryllis or magic lily in August to a depth of 5 inches. They will produce foliage in the spring which dies down by late summer. Clusters of 6 to 9 lily-like pink flowers borne on 3-foot stalks will appear in August of next year. It’s best to plant these bulbs in a permanent location in the landscape. They prefer not to be moved.
With hot dry weather comes the red spider mites. These tiny sucking creatures feed on all types of shrubs and flowers, leaving normally green leaves a specked white. Inspect your roses, evergreens and marigolds for signs of pale green coloration. To verify the presence of these pests, hold a white sheet of paper underneath the foliage and briskly tap the branch. Look closely at the white paper for tiny crawling dots or run your finger over some of the spots on the paper. If the spots streak red or black, you have spider mites.
If your spider mite infestation and damage is light, you may be able to discourage them with a forceful direct spray from the water hose. One of the reasons the populations of these mites become a problem in hot dry weather is that there is limited or no rainfall to wash them off the plants.
Severely infested annuals should be removed from the garden and destroyed. Your shrubs and perennials may require treatment with a miticide such as a summer oil spray or insecticidal soap.
Plan changes in your perennial plantings now. Autumn is usually the best time for moving and dividing perennials as the gardening pace has slowed considerably. Add new bulbs to your design at this time.
Mildew is a problem in the landscape in August on both ornamentals and vegetables. There are two different kinds of mold that are likely to affect your landscape: downy and powdery mildew.
The first of these, downy mildew, is a problem on beans, cucumbers and cantaloupes. This fungus disease causes yellow to dark areas on the upper surface of older leaves. Turn the leaf over and you’ll see a whitish or gray-colored mold in patches on the under surface. The mold may also occur on bean pods. Affected vines may be scorched or killed.
Powdery mildew appears as a white or brownish talcum-like growth on leaves and young stems of squash, pumpkins, cantaloupes and cucumbers. Look for it especially on the upper surface of leaves. It will also sometimes affect fruit. Severely infected plants will turn yellow, wither and die.
To control either downy or powdery mildew, use resistant varieties, practice crop rotation within your garden and maintain good weed control. It also helps to space plants properly. Overcrowding keeps humidity high and favors development and the spread of the diseases. Destroy residues of affected crops in the fall since they may serve as a source of new infections next year. There are really no effective fungicides for homeowners to use to control these diseases in vegetables so use the cultural controls as best possible.
Powdery mildew is a problem on a number of ornamentals in the landscape. These infestations occur most often in late summer when the days are hot and the nights are cool. Powdery mildew is an unusual disease because, unlike most fungal leaf disorders, it often develops under dry conditions. Some mildews, particularly those on roses, apples and cherries, are also increased by high humidity.
Prevention by cultural practices are the first defense. Also, grow resistant cultivars, space and prune plants to improve aeration and lessen shading and water early in the day at the base of the plants, not on the foliage. For most shrubs, the disease appears so late in the growing season that control is usually not necessary. After the diseased leaves have fallen in the fall, rake them up and destroy them. This will help to reduce the disease problem next year.
Don’t forget your fall vegetable garden. Crops like cabbage, cauliflower, broccoli, kale, spinach, lettuce and onions can be planted in August. It is also time to plant your root crops like beets, carrots, turnips and rutabagas. There are many advantages to having a fall vegetable garden. Late planting extends the usefulness of the garden, providing a continual supply of fresh vegetables and may yield higher quality crops than those you get from spring plantings. It’s also usually easier to control the weeds as many of the summer annual weeds are going to seed at this point.
Vegetables harvested in the fall may actually be better suited for canning and freezing than those grown earlier since they develop more slowly under early fall growing conditions. This will give you crops that are tastier and more tender.
Be sure to select fall vegetable varieties with a relatively short maturation time. 50 to 70 days is best. Although there’s always a possibility of an early frost, the autumns in this area tend to remain mild for quite a while and many of the crops suitable for planting now will hold up against anything short of a hard frost. One year I remember cutting broccoli in the garden a couple of days before Christmas!
Happy Gardening!!