Gardening Calendar for May

Week One:

• Begin planting gladiolus bulbs as the ground warms. Continue at 2-week intervals.
  
• Set out tomato plants as soils warm. Place support stakes alongside at planting time.
  
• Begin planting sweet corn as soon as white oak leaves are as big as squirrel ears.

Weeks Two and Three:

• Plant summer bulbs such as caladiums, dahlias, cannas and elephant ears.
  
• 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.

Weeks Three and Four:

• If spring rains have been sparse, begin irrigating, especially plants growing in full sun.
  
• 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.
  
• Set out peppers and eggplants after soils have warmed.
  
• Plant sweet potatoes now.

All Month:

• Apples, crabapples and hawthorns susceptible to rust disease should have protective fungicidal sprays applied, beginning when these trees bloom.
  
• Growing lettuce under screening materials will slow bolting and extend harvests into hot weather.
  
• Keep bluegrass cut at 1.5 to 2.5 inch height.
  
• Mulch blueberries with pine needles or sawdust.

Missouri Botanical Garden