May is finally here, and we can begin our gardening projects. It is important to remember that for our area May 15 is the average last frost date. However, Memorial Day planting still is a good idea for cold-sensitive vegetable plants such as peppers, eggplant, squash and tomatoes, and cold-sensitive annual plants including impatiens, begonias, coleus and potato vines.
Woody plant care
Trees and shrubs can be successfully planted this month. Early in the morning on a cloudy day will provide optimum conditions for the new transplants. Provide 1 inch of water a week for the first year.
Prune spring flowering trees and shrubs immediately after bloom.
Roses will need attention this month. Remove dead canes from the plant and prune, if necessary, the center of the rose bush to keep that area open to provide good air circulation. Fertilize roses with a 20-20-20 liquid solution.
Annual and perennial care
Plant hardy annuals mid-month and tender annuals at the end of the month. If your annuals are in baskets, they will need frequent watering on warm, windy days. Harden annuals before planting outside and avoid fertilizing for two weeks.
Annual climbing vines can be a great addition to your garden. Most vines are quick growing and will produce a large blossom display for most of the summer. Some suggestions for annual vines include Hyacinth Bean, Nasturtium, Morning Glory, Sweet Pea and Black-Eyed Susan Vine.
As perennials emerge, check them for winter damage and decide if they need to be divided.
May lawns should be mowed at 2 to 2½ inches. Grass clippings can be left to return nutrients to the soil. Wait to fertilize until early September.
Fruit and vegetable care
Fruit trees can be planted this month. When selecting trees, look for healthy trees that are certified virus safe. Apple, pear, peach, plum and apricot trees will need 6 to 8 hours of full sun exposure. All will need annual pruning with peaches and apricots needing a very heavy pruning to remove excess fruit.
Mid-May is the time to plant corn, spinach, summer squash and snap beans.
Growing chard will provide you with a plant both edible and attractive. It can be planted early to mid-spring by spacing seeds 4 to 6 inches apart. Harvest when the leaves are young and tender (about 8 to 12 inches long). Keep chard in the refrigerator until ready to use.
Indoor plant care
Houseplants can be gradually exposed to outside protected areas in mid to late May. Do not leave them in late afternoon sun. Tropicals may begin to be outside when night temperatures are in the 40s.
Amaryllis bulbs in pots can be moved to a protected spot in the garden to receive morning sun. They should be fertilized twice a month with a dilute 15-30-15 solution.
Herbs require at least 6 hours of sun a day and are happy with average soil and water conditions. If herbs are being grown in a container, they will need more water, dilute fertilizer every two weeks and they will benefit from pinching back to retain a more compact plant form.
Harvest herbs early in the day, anytime before flowering occurs.
• The Master Gardeners are available to answer your questions from 9 a.m. to noon Monday through Friday at the University of Illinois Extension DeKalb County office in the Farm Bureau Center for Agriculture, 1350 W. Prairie Drive in Sycamore. Call 815-758-8194 or email DeKalb_mg@extension.uiuc.edu. Walk-ins are welcome.