Tidewater Gardening - August 2012

Summer Doldrums

K. Marc Teffeau

August is the time when most activities slow down in the landscape. We usually focus on maintenance efforts like cutting the grass, if it has rained and the grass is still growing, and harvesting vegetables in the garden. We can be proactive, however, and start to look at the upcoming fall season.
As we get into August, perfect conditions for powdery mildew usually develop. Powdery mildew diseases attack a great many ornamentals, most often in late summer when the days are warm and nights cool. Some mildews, particularly those on roses, apples and cherries, also are increased by high humidity.
Prevention with proper cultural techniques is the first defense. Grow resistant varieties; space and prune plants to improve aeration and lessen shading; water early in the day and at the base rather than on leaves; and reduce nitrogen applications to avoid excessive late-season growth.
You can apply over-the-counter fungicides to certain plants to try to keep the mildew under control, but it is usually a difficult battle. For plants like lilac, just ignore the problem and be sure to remove all diseased leaves during your fall cleanup to prevent a source of infection next year.
August is not the time to be putting down mulch. In fact, you should examine any shrubs where the mulch is touching the stems. Shrubs may not develop mature stem tissue where the mulch is touching. To harden stems so they can withstand early frost damage, remove about 2 to 3 inches of the mulch from the base of the stems in mid-August.
During hot, dry August days, avoid deep cultivation of your flower beds. Loosening the soil under these conditions reduces water retention and can damage surface roots. Plants often look much worse after cultivation.
Fruit plants also need your attention now. Fertilize your strawberries in August. For plants set out this spring, apply 4 to 6 oz. of ammonium nitrate, or 12 to 18 oz. of a 10-10-10 complete fertilizer per 25 linear feet of row. Spread the fertilizer uniformly in a band, 14” wide over the row while the foliage is dry. Brush the fertilizer off the leaves to avoid leaf burn. For plants in the second year of growth, increase the application rate to 6 to 8 oz. ammonium nitrate or 18 to 24 oz. of 10-10-10 per 25 ft. of row.
If you want to use an organic fertilizer equivalent, check the bag label for the recommended application rate. Strawberries set their fruit buds in the late summer/early fall for the next year, so they need a lot of fertilizer at this time.
It is also important to maintain adequate water to the strawberries, blueberries and bramble crops now. A long, slow soaking around the plants during the dry spells of August will ensure good fruit bud production for next year’s crop.
Don’t forget to prop up the branches of fruit trees that are threatening to break under the increased weight of ripening fruit. Be sure to make a mental note on how to prune your trees next June to reduce the number of fruit the tree is carrying. This will improve the size and quality of the remaining fruit.
Watering is critical for fruit trees at this time – especially peaches. To get the flesh to swell and to produce large fruit, be sure the tree gets adequate water about two weeks before the tree is to be harvested.
After harvesting the fruit, reduce the number of pests on your trees for next year by picking up and composting all fallen fruit. Worms hide in the fallen fruit and then pupate in the soil, ready to lay eggs in the spring.
In August you can plan to do some planting of fall and early spring flowers. Order peony roots now for planting in September. You can plant these roots about a month before the average first frost date. Planting should be completed before the first killing frost occurs.
Plant crocus, sternbergia, colchicum and other fall-flowering bulbs as soon as they become available at garden centers. Crocus and sternbergia need full sun while colchicum can be planted in areas receiving light shade.
Bulbs of the hardy amaryllis or magic lily can be planted in August. They will produce foliage in the spring that dies down by late summer. Clusters of 6 to 9 lily-like pink flowers borne on 3-foot stalks appear in August. The bulbs will live almost indefinitely and grow better if not disturbed.
August is a good time to sow perennial seeds, especially for plants like lupine and delphinium. Pansy, forget-me-not and English daisies can also be sown this month.
If the August heat has taken a toll on our flower beds leaving them ragged looking, don’t despair! Many annuals will bounce back with the cooler weather of fall. Now is the time to renovate the flower bed, removing any dead plant materials and clean up spent blossom and seed heads. Put a hold on any fertilization until next spring.
If your marigolds have been wiped out by spider mites, and powdery mildew has taken out the zinnias, replace them with cool-season annuals like salvia, coleus and petunias. If the local garden center is not carrying any fall annual transplants, start your own now from seed. If we have a mild fall, you can have flowers right through November.
Some summer annuals don’t need replacing, just a trimming to get them to bush out and start blooming again. Good plants for this pruning treatment include begonia, coleus, annual vinca and petunias.
Don’t forget to water the landscape plantings, especially those that flower next spring. Water shrubs deeply once a during August. Many plants, including azaleas, rhododendrons, camellias and lilacs are setting flower buds now for next spring’s flower display. Water early in the morning and apply the water to the base of the plants, not the foliage. Do not fertilize or prune these plants now.
Start transplants of broccoli, cabbage, cauliflower, Brussels sprouts and lettuce varieties now. Keep the produce picked on a daily basis to encourage continued production through the fall.
Make one more planting of an early-maturing green bean variety in early August. Root crops like beets and turnips can be seeded. Plant a crop of Sugar Snap or Sugar Ann edible pea pods for a fall harvest, too.
August is an excellent time to seed a fall salad garden. This year I planted a blend of salad greens in the garden and we have really enjoyed it. This mesclun included cut-and-come-again greens like leaf lettuces, arugula, mustard and others. For what you would pay for two weeks worth of salad greens for a family of four, you can buy more than enough seed to keep you in salad all fall and well into winter.
Choose from among the many leaf lettuces, including All American Section winners: Red Sails, Buttercrunch, Ruby and Salad Bowl. Romaines can take the cold, so try Rouge d’Hiver and Freckles for good color. Mix in some Lollo Rossa, Arctic King, Winter Marvel and North Pole for an outstanding winter collection.
You can sow each type of seed separately, or create your own personal mesclun blend. You can mix all the seeds together in a bowl and then scatter them on bare soil – thicker than normal. Make an 18-inch-wide swath through a garden bed, or edge your sidewalk leading to your front door.
The greens will come up in a colorful carpet. By the time the plants are a few inches tall they will need thinning. Pull up plants at random for an instant salad of baby greens.
Since you will be planting in the heat of summer, sow the seed in a partly shaded spot or provide shade with spun polyester cloth to keep them cooler. Mist lightly during the day to refresh the seedlings and young plants. Other wise they require no different care than spring-sown seeds.
Growing spinach in the spring can be a challenge as it doesn’t like the late-spring heat. In the fall, it is happy with the cooling weather. Be sure to avoid any varieties that are labeled “summer spinach.” As with the other plants for fall harvest, sow the seed in a partially shaded area to keep the soil from getting too warm.
Happy Gardening!