Tidewater Gardening May 2007

Moving Into May

by

K. Marc Teffeau

     Did your landscape survive the wacky early cold April? As T.S. Elliot wrote, “April is the cruelest month.” We need to take stock of the damage in May. There should be no long-term damage, but if you are a home fruit grower and are anticipating peaches, apricots or plums, you might have lost all or part of the crop. By now, if the flowers survived the cold, you should see some small fruit forming.
      There is a lot of maintenance work to be done in the landscape. Hopefully your rhododendrons still flowered, even with the early cold April temperatures. To keep the plants flowering at their best, it is important to deadhead the spent flowers immediately after flowering. The old clusters should be snapped off when partly dry, but remove with care in order not to decrease or prevent bloom next year.
      If you need to do any pruning on other spring flowering shrubs, now is the time to do it. Whack back the forsythia that has overgrown. Remove the spent flower clusters of the lilacs and do some renewal pruning to get them back into shape. That spirea that has spread all over the place may need some serious cutting to get it back to a manageable size. The general rule of thumb is not to take more than one-third of the plant out at any one cutting, but some of our more common spring flowering shrubs can be severely pruned if need be.
      Did you plant shade trees or shrubs in April? Regularly water newly planted trees and shrubs during the first year or two to help establish a good root system. They need at least one inch of water each week. It is better to water deeply once a week rather than watering lightly every day. The former practice encourages deep, drought-resistant roots while the latter practice encourages surface roots that may suffer during dry spells.
      Be careful with heavy clay soils. Sometimes if soil has poor drainage you can kill the newly planted tree or shrub with kindness by overwatering. It is also important to mulch to conserve moisture and control weeds, but PLEASE – no “volcano” mulches where the mulch is piled up 7 or 8 inches against the stem of the tree. I see this all the time in commercial landscape plantings and the maintenance contractors who are doing the mulching should know better.
      You can still plant trees and shrubs in May, just make sure that they are attended to during the summer.
      Looking for something different in the line of patio container flowers this year? Consider Calla lilies. They are not hardy in our area but can be planted for summer color, and then the rhizomes can be stored in dry material for the winter. Being tropical, they can take the heat and full sun on a patio, porch or deck. In addition to adding color, they are excellent as cut flowers.
      Two new introductions from the van Bourgondien Bulb Company are ‘Selina’ and ‘Bolero.’ ‘Selina’ has a unique coloration with bright orangish-yellow flowers with a broad red edge. ‘Selina’ is deer-resistant and will bloom from early June to early August. ‘Bolereo’ has a very deep red color with a creamy white throat and will flower from mid-May through late July.
      These flowers like lots of nutrients, so supplement your watering weekly with a water-soluble fertilizer. In the late summer, after the flowers fade, reduce the amount of water and allow the plants to dry out. Dig the rhizomes and store in dry material for the winter.
      The good news is that the soil is warming up and the last frost date has passed so we can get some of our spring plantings into the garden. It is time to make your first sowing of green beans, cucumbers, squash, sweet corn, and a second seeding of lettuce in the vegetable garden. Transplants of tomatoes, eggplants and peppers can now be placed in the garden.
      Transplants become less stressed when they are set out on a cloudy, calm day. We usually don’t have time to wait around for the perfect conditions so we have to take precautions. Strong sun and wind are hard on new transplants, so set out plants in the late afternoon when the wind comes down and the plants have over night to acclimate. Provide shade and wind protection with berry baskets, small crates or screens. I would wait until June, however, to mulch the transplants in the vegetable garden so as to give enough time for the soil to fully warm up.
      Have you ever set out a tomato transplant one day, just to find it cut off at the soil level the next? Your problem might be cutworms. To prevent cutworm damage on the transplants, cut the tops and bottoms from small coffee cans. Place the cans over the transplants in the early evening. Next morning, remove them so the plant can get full sun. Repeat every night for about a week until the plants become established. A telltale sigh that you have cutworms in the garden is pencil-diameter sized holes in the ground. The cutworms come out at night and clip the transplants off at ground level.
      Other early spring insect pests active now include aphids, cabbageworms, cucumber beetles and Colorado potato beetles. Aphids seem to appear overnight and suck the sap from the leaves and tender new growth, but usually little permanent damage is done. A number of parasites and predators, notably the ladybird beetle, help keep this insect pest in check. A forceful spray from the garden hose will also help to keep aphids under control. For serious infestations, try using an insecticidal soap or a botanical insecticide.
      Keep an eye out for cabbageworms in the cabbage and broccoli plantings. They can ruin the heads if not kept under control. How many times have you gone out to the vegetable garden, picked a couple of nice heads of broccoli, brought them inside and steamed them for dinner, only to find a couple of blanched cabbageworms on your dinner plate? Don’t worry, the cabbageworms are a source of protein, but most of us prefer being served protein in the form of a steak from the grill. Use a biological control called B.t. or Dipel to control these worms.
      Striped and spotted cucumber beetles are voracious feeders on many vegetables including squash, corn, cucumbers, melons and beans. They also transmit the bacterial wilt disease that causes the plants to rapidly wilt and die. These must be controlled early with floating row covers. Protection in the early stages of growth is important, however, when the plants start to flower, especially squash and cucumbers, you will need to remove the row covers to allow bees access to pollinate the flowers.
      Try using a homemade spray made up of horseradish roots and leaves, garlic, peppercorns, hot peppers and green onions. Blend these ingredients up in your blender and then place in a pail with one cup of liquid detergent. Stir and let set overnight. Use one-half cup of the solution to one quart of water and spray on the plants.
      Spring lawn care usually consists of mowing the lawn at the proper height with a sharp blade. Mow the lawn at least 2½ to 3 inches tall. The taller mowing height will help keep the crabgrass under control by not letting the sunlight hit the soil surface where the crabgrass seeds lie. Crabgrass seed needs light to germinate.
      If you are replacing an old lawn mower, buy one that mulches the grass clippings and returns them to the lawn. This will return the valuable nutrients found in the clippings back to the turf. I do not recommend fertilizing the lawn in May. If you missed an early spring feeding, wait until Thanksgiving for fall fertilization.
      Now is the time to set out marigolds, petunias, ageratums and fibrous begonias in the flower garden. All are good border plants. Multiflora petunias withstand heat better than other types and are more attractive throughout the summer. They are more resistant than other types to botrytis, a disease that cripples petunias, especially in damp weather. They also branch more easily, meaning less maintenance. Multifloras are most useful for massed effects in beds.
      You can also set petunia plants among fading tulips or daffodils to hide the unsightly wilting leaves. After the bulb foliage begins to fade, you can tie the leaves in gentle knots to neaten them, but don’t remove them until they have dried completely.
      Happy Gardening!!!