Monthly Horticulture Tips 

Oklahoma Cooperative Extension Service
Division of Agricultural Sciences and Natural Resources
Oklahoma State University

June

By David Hillock

Download the entire list of tips here

General Landscape

  • Find someone to water plants in the house and garden while on vacation. Harvesting vegetables and mowing the lawn are a must and imply that someone is home.
  • Mulch ornamentals, vegetables, and annuals to reduce soil crusting, and to regulate temperatures and moisture during hot summer months. Mulching will reduce about 70 percent of the summer yard maintenance.
  • Remain alert for insect damage. Add spider mite to the list. Foliage of most plants becomes pale and speckled; juniper foliage turns a pale yellowish color. Shake a branch over white paper and watch for tiny specks that crawl. Watch for first generation fall webworm. (EPP‑7306)

Turfgrass

  • Fertilize warm-season grasses at 1 lb. N per 1,000 square feet. Don’t fertilize fescue and other cool-season grasses during the summer.
  • Dollar spot disease of lawns can first become visible in mid-May. Make certain fertilizer applications have been adequate before applying a fungicide. (EPP-7658)
  • Seeding of warm-season grasses should be completed by the end of June (through July for improved varieties such as Riviera and Yukon to reduce winterkill losses. (HLA-6419)
  • Brown patch disease of cool-season grasses can be a problem. (HLA-6420)
  • White grubs will soon be emerging as adult June Beetles. Watch for high populations that can indicate potential damage from later life cycle stages as grubs in the summer.

Fruit and Nut

  • Renovate overgrown strawberry beds after the last harvest. Start by setting your lawnmower on its highest setting and mow off the foliage. Next thin crowns 12-24 inches apart. Apply recommended fertilizer, preemergence herbicide if needed and keep watered. (HLA-6214)

Trees and Shrubs

  • Vigorous, unwanted limbs should be removed or shortened on new trees. Watch for forks in the main trunk and remove the least desirable trunk as soon as it is noticed. (HLA-6415)
  • Pine needle disease treatments are needed again in mid-June.
  • Remove tree wraps during the summer to avoid potential disease and insect buildup.
  • Softwood cuttings from new growth of many shrubs will root if propagated in a moist shady spot.
  • Protect trees from lawnmowers and weed eaters by mulching or using protective aerated covers.

Flowers

  • Pinch back leggy annuals to encourage new growth. Fertilize and water appropriately.
  • Feed established mums and other perennials.
  • When picking fresh roses or removing faded ones, cut back to a leaflet facing the outside of the bush to encourage open growth and air circulation.
  • Stake tall perennials before toppling winds arise.