The Homeowners Column

The Homeowners Column

April Activities in the Garden

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

Spring is finally here. Gardeners are trembling to get outside and do something…..anything. If you are wondering what to do and enjoy having lists, here are your activities for April. Get out your red pen and start checking.

General

  • Average last frost date is approximately April 21. For tender plants such as impatiens, basil and tomatoes, wait until after May 10 before planting.

Flowers

  • Begin planting and dividing most perennials except bearded iris and peony. Iris are divided in August. Peonies are divided in September.
  • Plant pansies and hardy annuals.
  • Finish pulling back mulch from around perennials and roses.
  • Prune summer and fall blooming clematis.
  • Spray emerging peonies with fungicide if diseases such as botrytis have been a problem in the past.
  • Plant bare root plants before they leaf out. Be sure to soak plants in warm water for at least 2 hours before planting.
  • Ornamental and native grasses should be cut down within a few inches of the ground before growth starts.
  • Houseplants and overwintering tropicals can be trimmed, repotted and fertilized.
  • Late April severely prune sage, butterfly bush, Russian sage and Caryopteris to stimulate growth. Wait until lavender shows new growth before pruning off winter-killed stems.

Lawn

  • Mow lawn to two inches removing no more than 1/3 of leaf blade at any one mowing.
  • Establish or renovate turf by seed or sod. Prepare soil properly and get good seed to soil contact. Select turf mixes and blends appropriate to the site and to maintenance practices.
  • Apply preemergent crabgrass control to areas with past history of annual grassy weeds when the soil temperatures reach 55 degrees F for at least three consecutive days (generally late April). Do not reseed turf at the same time unless siduron is used as the herbicide.
  • Use postemergence herbicides for actively growing broadleaf weeds as necessary. Consider spot treatment rather than complete lawn application.
  • Reduce thatch if more then .5 inch by using core aerifiers or vertical mowers.
  • Core aerifiers may be used to reduce soil compaction.

Trees/Shrubs

  • Continue planting trees and shrubs.
  • Prune spring flowering shrubs such as forsythia soon after bloom. Use renewal pruning by removing oldest stems at soil level.
  • Examine trees and shrubs for winter injury. Prune out and remove all dead and diseased wood.
  • Fertilize if not done in fall and if soil test or reduced growth indicates need.
  • Scout for spider mite damage on spruce.
  • Begin fungicide treatments for apple scab on crabapples if it has been a problem in the past. Consider replacing trees with disease resistantcultivars.

Vegetables

  • Add compost to garden.
  • If needed, till garden when soil permits. Squeeze a handful of soil. It should crumble apart easily. Do not work when soil is too wet.
  • Plant seeds of frost tolerant plants such as spinach, lettuce, carrot, beet, chard, parsnip and radish.
  • Plant or divide rhubarb.
  • Plant asparagus crowns.

Fruits

  • Plant strawberries. Pinch off first year flowers to encourage strong root systems.
  • Plant fruit trees, grapes and brambles such as raspberry and blackberry.

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