The Homeowners Column

The Homeowners Column

Garden Activities for Days of May

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

First I believe I should apologize to all the honeys out there that will be the recipients of the following "honey do" list. Sorry but as in life, so goes the garden. Timing is everything and every hive has its worker bees.

Flowers

  • Remove spent flowers on spring flowering bulbs, but wait until foliage ripens naturally before removing.
  • Travel to Allerton Park in Monticello to enjoy the peony garden.
  • Set flower supports early. Let plants grow through them.
  • Plant tropical water lilies when water temperature is over 55ยบ F.
  • Over-wintered tender annuals or tropicals such as hibiscus, gardenia, mandevilla, and geranium may be pruned, cleaned, and fertilized. Move outdoors once chance of frost has passed, generally mid-May.
  • Begin pinching top 1-2 inches of new growth on chrysanthemums to encourage full bushy plants. Stop pinching in early July.
  • With clump-forming perennial flowers such as asters, beebalm, and tall phlox pinch out the top growth of the front half of the clump. This technique extends the bloom time since the front half will bloom about 2 weeks later and also shapes the clump into cultured tiers.
  • Experiment with removing a few inches of the top growth of tall sedum to keep it from flopping apart. Smaller flowers will arrive later, but will be more numerous. If the plants are getting plenty of sun, this may be a good alternative to staking.
  • Severely prune sage, butterfly bush, Russian sage, and Caryopteris to stimulate growth.
  • Remove winter-killed stems on roses.

Lawns

  • If not accomplished in April fertilize in early May with one pound of actual nitrogen per 1,000 square feet. Slow release nitrogen forms are preferred.
  • Finish any seeding.

Fruits

  • Pick strawberries. Remove any rotten fruit to reduce picnic beetle populations.
  • Continue control of insects and diseases on fruit trees.

Trees/Shrubs

  • Pinch azalea and rhododendron blossoms as they fade. Fertilize after bloom with fertilizer for acid-loving plants.
  • Prune spring flowering shrubs such as lilac, weigela, viburnum, and forsythia soon after bloom using renewal method by pruning oldest stems to the ground.
  • Monitor pines especially Scotch and mugho for caterpillar-like sawfly larvae on new shoots. Hand removal is effective or insecticide sprays of spinosad, neem oil or permethrin.
  • Scout for pine needle scale and oystershell scale crawlers by circling stems with inverted black tape. Young crawlers are present about the time bridal wreath spirea is in late bloom or has finished bloom, typically late May but this year everything seems to be about two weeks early. Timing is crucial for scale control since sprays are most effective on the young crawlers. Insecticides to use include insecticidal soaps and summer oil sprays.
  • Early June scout for and spray euonymus scale when catalpa starts to bloom.

Vegetables/Herbs

  • Mid-May plant sweet corn, squash, tomatoes, eggplant, sweet potato, and other warm loving crops.
  • Thin carrots and beets to allow root development.
  • Continue to harvest asparagus and rhubarb.
  • Prune sage to stimulate new growth.
  • Plant transplants or seeds of annual herbs such as basil and dill. Sow extra dill or parsley for the swallowtail caterpillars.

General

  • Practice good sanitation. Remove and destroy diseased leaves.
  • Mulch with organic mulches such as wood chips to reduce weeding and conserve moisture.
  • Be sure to read, understand, and follow all pesticide label directions.

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