May Horticulture Tips	Jan	Feb	March	April	May	June
	July	Aug	Sept	Oct	Nov	Dec

Trees

• Ash Sawfly larvae- Light green worms on ash trees. Large trees-not practical to control, tree will continue to leaf out. Small trees- control with Sevin, Malathion, Orthene, Eight
• Wooly aphid- Curled up and distorted leaves on ash trees. Control: Bt, Sevin, Malathion, Orthene, Eight
• Pine Sawfly larvae- Green worms on pine trees. Control: Sevin, Malathion, Orthene, Eight
• Honeylocust l eaf hoppers- Honeylocust tree not leafing out, leaves eaten by leafhopper. Control: small trees use Sevin, Malathion, Orthene, Eight
• Scale insects- Control: Horticulture oil, Acephate (Orthene), Malathion
• Dothistroma needle blight- Needle dieback on pine. Control with applications in mid-May and mid-June, using Bonide liquid copper fungicide, Bordeaux mixture
• Rhizosphaera needlecast on spruce- Control with applications of Chlorothalonil, Bordeaux mixture
• Mulch around newly planted trees and shrubs. This practice reduces weeds, controls fluctuations in soil temperature, retains moisture, prevents damage from lawn mowers and looks attractive.

Lawn Care

• Seed Bluegrass lawn- April 1 to May 15. Or overseed bare patches in the lawn.
• Plant buffalograss- May 15
• Fertilize Bluegrass lawn- April 20 to May 10
• Apply pre-emergent herbicide for crabgrass control when soil temperature is consistently 55-60 degrees Fahrenheit
• Apply grub control- using Merit or GrubX, apply from May through June, but before July 1st
• Bluegrass billbug- control withcarbaryl (Sevin)
• Sharpen your lawn mower blade monthly
• Apply herbicide to control broadleaf weeds
• Lawns maintained at the correct height are less likely to have disease and weed infestation. Kentucky bluegrass and tall fescue should be mowed at two or three inches in height. Mow frequently, removing no more than one third of the blade at each cutting.

Vegetable Garden

• Approximate last frost date in Lancaster County- May 10
• Harvest asparagus by cutting or snapping spears
• Plant warm season vegetable seeds (bean, squash, corn, cucumber)- May 15
• Thin seedlings of early-planted garden crops
• Turn compost pile
• Cabbage loopers and imported cabbage worms are green worms. They leave large holes in the leaves of plants in the cabbage family. For control, caterpillars can be picked off by hand or sprayed with Bt (Bacillus thuringiensis), a natural, non-toxic preparation available by various trade names.
• Newly transplanted vegetable plants should be protected from cutworms with collars. Cut strips of cardboard two inches wide by eight inches long, staple them into circles and place them around the plants. Press the collar about one inch into the soil. These collars will fence out the cutworms and protect the stems of the vegetable plants.
• Stay out of the garden when the vegetable plant leaves are wet. Walking through a wet garden spreads disease from one plant to another.
• Four or five layers of newspaper will serve as an effective mulch in the garden. Cover it with grass clippings or straw to prevent it from blowing away.

Ornamentals

• Plant wildflowers- May 15
• Prune spring flowering shrubs- after they are done blooming, approximately late May/early June
• Plant gladioli bulbs in late May.
• Set out marigold, petunia, ageratum and fibrous begonia transplants. All are good border plants.
• Watering roses with soaker hoses or drip irrigation will reduce the spread of black spot disease.
• Plant ground covers under shade trees that do not allow enough sunlight to grow grass. Vinca minor or English ivy are ground cover plants that grow well in shade.
• Grass clippings can be used as a mulch in flower beds and vegetable gardens if allowed to dry well before use. Never use clippings from a lawn that has been treated with a herbicide.

Garden Planning

• Plan a landscaping project on paper first. Do not over plant. Be sure you know the mature size of each plant and allow for growth.