May Gardening Calendar

Courtesy of:
Missouri Environment & Garden
MU IPM Program

ORNAMENTALS:Weeks 1-4: Apples, crabapples and hawthorns susceptible to rust disease should have protective fungicidal sprays applied beginning when these trees bloom.

Weeks 1-4: Pinch azaleas and rhododendron blossoms as they fade.  Fertilize azaleas after bloom. Use a formulation which has an acid reaction.

Weeks 1-2: Canker worms (inch worms) rarely cause permanent damage to ornamentals. Use Bt if control is deemed necessary.

Weeks 1-2: Don't remove spring bulb foliage prematurely or next year's flower production will decline.

Week 1: Continue monitoring pines, especially Scotch and mugo, for sawfly activity on new shoots.

Week 1: Begin planting gladiolus bulbs as the ground warms. Continue at 2-week intervals.

Week 1: Plant hardy water lilies in tubs or garden pools.

Weeks 2-4: Scale crawlers are active now. Infested pines and euonymus should be treated at this time.

Weeks 2-3: Plant summer bulbs such as caladiums, dahlias, cannas and elephant ears.

Weeks 3-4: Begin fertilizing annuals. Continue at regular intervals.

Weeks 3-4: Trees with a history of borer problems should receive their first spray now. Repeat twice at 3-week intervals.

Weeks 3-4: Bulbs can be moved or divided as the foliage dies.

Week 4: Pinch back mums to promote bushy growth.

VEGETABLES
Weeks 1-4: Place cutworm collars made from cardboard strips around young transplants.
Weeks 1-4: Growing lettuce under screening materials will slow bolting and extend harvests into hot weather.

Weeks 1-4: 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.

Weeks 1-2: Plant dill to use when making pickles.

Week 1: Keep asparagus harvested for continued spear production. Control asparagus beetles as needed.

Week 1: Begin planting sweet corn as soon as white oak leaves are as big as squirrel ears.

Week 1: Isolate sweet, super sweet and popcorn varieties of corn to prevent crossing.

Week 1: Thin plantings of carrots and beets to avoid overcrowding.

Week 1: Control caterpillars on broccoli and cabbage plants by handpicking or use biological sprays such as B.t.

Week 1: Set out tomato plants as soils warm. Place support stakes alongside at planting time.

Weeks 2-3: 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.

Weeks 2-3: Remove rhubarb seed stalks as they appear.

Week 2: Watch for striped and spotted cucumber beetles now. Both may spread wilt and mosaic diseases to squash and cucumber plants.

Weeks 3-4: Set out peppers and eggplants after soils have warmed.
Week 4: Make new sowings of warm-season vegetables after harvesting early crops.

http://ipm.missouri.edu/MEG/2013/4/May-Gardening-Calendar/