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Johnson County

Research-based Information You Can Trust — Localized for your needs

Johnson County
11811 S. Sunset Drive
Suite 1500
Olathe, KS 66061

Office Hours:

Monday - Friday,
8:30 a.m. - 5 p.m.

(913) 715-7000
(913) 715-7005 fax

Map to our office

K-State Research and Extension is committed to making its services, activities and programs accessible to all participants. Reasonable accommodations for persons with disabilities may be requested by contacting Johnson County Extension at (913)715-7000. Notify staff of accommodation needs as early as possible.

Kansas State University Agricultural Experiment Station and Cooperative Extension Service

K-State Research and Extension is an equal opportunity provider and employer.

May Garden Calendar

Vegetables and Fruits

  • Plant tomato, pepper, and eggplant transplants in early May
  • Seed sweet corn, cucumbers, squash, beans, and other warm season vegetables
  • Lightly cultivate soil with a hoe to control weed growth
  • Mound soil around potato plants to encourage tuber formation
  • Harvest fresh asparagus until the spear size decreases
  • Remove rhubarb seed stalks to encourage leaf growth
  • Plant kitchen herbs for summer use in dishes or food preservation
  • Treat fruit trees with needed pesticides to control insects and disease
  • Thin heavy fruit set on apples to increase fruit size and next year's crop


  • Plant annual flowers for summer color
  • Continue to plant and divide perennials
  • Mulch perennial and annual gardens for weed control and moisture retention
  • Begin pinching chrysanthemums for bushier plants
  • Do not remove foliage from spring bulbs until it dies down naturally, this develops stronger blooms for next year
  • Plant container gardens and hanging baskets using a good quality potting mix
  • Keep a garden journal for permanent reference


  • Reduce thatch layers from zoysia by verticutting or core aerating
  • Sod or sprig zoysia lawns to fill in bare areas
  • Fertilize zoysia lawns with high nitrogen to promote green up and summer growth
  • Mow zoysia at 1 to 2 inches tall
  • Apply slow release nitrogen fertilizer to bluegrass and tall fescue to promote summer growth if watering during the summer. Lower maintenance lawns skip this application
  • Mow bluegrass and tall fescue at 3 inches
  • Spot treat broadleaf weeds
  • Withhold early summer watering until needed to promote more drought tolerant lawns

Trees and Shrubs

  • Plant new trees and shrubs
  • Prune spring flowering shrubs after bloom to shape plant and encourage flowers next year
  • Mulch around young trees and shrubs to conserve moisture and control weed growth
  • Water young ornamentals as needed
  • Remove tree wraps for summer growth
  • Remove tree stakes that have been in place more than one growing season
  • Fertilize trees to help increase growth rates
  • Caution, use line trimmers around trees and shrubs so as not to damage tender bark


  • Move plants outdoors for summer by gradually increasing the exposure to sunlight
  • Fertilize plants to promote summer development
  • Rotate plants to develop a well-rounded plant
  • Wash dusty leaves in the shower under room temperature water
  • Four to six inch cuttings are a great way to start new plants, root in potting mix under low light
  • Repot plants into a one inch larger pot
  • Check for insects

Return to Garden Calendar

K-State Research and Extension Johnson County Master Gardener logo

Have questions? The Garden Hotline is staffed by trained EMG volunteers and Extension staff who will assist you with questions.

Phone: (913) 715-7050

Email: garden.help@jocogov.org