May

Ornamentals 

• Apples, crabapples and hawthorns susceptible to rust disease should have protective fungicidal sprays applied beginning when these trees bloom.
•  Pinch azaleas and rhododendron blossoms as they fade. Double flowered azaleas need no pinching.
•  If spring rains have been sparse, begin irrigating, especially plants growing in full sun. 
• Fertilize azaleas after bloom. Use a formulation which has an acid reaction. 
• Canker worms (inch worms) rarely cause permanent damage to ornamentals. Use Bt if control is deemed necessary.
•  Don't remove spring bulb foliage prematurely or next year's flower production will decline. 
• Continue monitoring pines, especially Scotch and mugo, for sawfly activity on new shoots. 
• Begin planting gladiolus bulbs as the ground warms. Continue at 2-week intervals. 
• Plant hardy water lilies in tubs or garden pools.
•  Scale crawlers are active now. Infested pines and euonymus should be treated at this time.
•  Plant summer bulbs such as caladiums, dahlias, cannas and elephant ears. 
• Begin planting warm-season annuals.
•  Begin fertilizing annuals. Continue at regular intervals. 
• Trees with a history of borer problems should receive their first spray now. Repeat twice at 3-week intervals.
•  Bulbs can be moved or divided as the foliage dies.
•  Pinch back mums to promote bushy growth.

 Lawns

•  Keep bluegrass cut at 1.5 to 2.5 inch height. Mow tall fescue at 2 to 3.5 inch height. 
• Mow zoysia lawns at 1.5 inch height. Remove no more than one-half inch at each mowing. 
• Apply post-emergence broadleaf weed controls now if needed. 
• Zoysia lawns may be fertilized now. Apply no more than 1 pound of actual nitrogen per 1000 square feet
• . Watch for sod webworms emerging now. 

Vegetables 

• Place cutworm collars around young transplants. Collars are easily made from cardboard strips. 
• Growing lettuce under screening materials will slow bolting and extend harvests into hot weather. 
• Slugs will hide during the daytime beneath a board placed over damp ground. Check each morning and destroy any slugs that have gathered on the underside of the board. 
• Plant dill to use when making pickles. 
• Keep asparagus harvested for continued spear production. Control asparagus beetles as needed. 
• Begin planting sweet corn as soon as white oak leaves are as big as squirrel ears.
•  Isolate sweet, super sweet and popcorn varieties of corn to prevent crossing. 
• Thin plantings of carrots and beets to avoid overcrowding. 
• Control caterpillars on broccoli and cabbage plants by handpicking or use biological sprays such as B.t.  
• Set out tomato plants as soils warm. Place support stakes alongside at planting time.
•  Place a stake by seeds of squash and cucumbers when planting in hills to locate the root zone watering site after the vines have run. 
• Remove rhubarb seed stalks as they appear.
•  Watch for striped and spotted cucumber beetles now. Both may spread wilt and mosaic diseases to squash and cucumber plants.
•  Set out peppers and eggplants after soils have warmed. Plant sweet potatoes now. 
• Make new sowings of warm-season vegetables after harvesting early crops. 

Fruits 

• Mulch blueberries with pine needles or sawdust.
•  Don't spray any fruits while in bloom. Refer to local Extension publications for fruit spray schedule. 
• Prune unwanted shoots as they appear on fruit trees. 

Miscellaneous 

• Birds eat many insect pests. Attract them to your garden by providing good nesting habitats. 
• Herbs planted in average soils need no extra fertilizer. Too much may reduce flavor and pungency at harvest. 
• Take houseplants outdoors when nights will remain above 50 degrees. Most prefer only direct morning sun.
•  Watch for fireflies on warm nights. Both adults and larvae are important predators. Collecting may reduce this benefit. 
• Sink houseplants up to their rims in soil or mulch to conserve moisture. Fertilize regularly. 

 Pests and Problems 

Hold off planting warm season vegetables, such as tomatoes, eggplants, vine crops; herbs, and warm-season annuals until the soil warms, usually in mid to late May. 

Continue to inspect for and treat for holly leafminers as new leaves emerge.