Delaware County Cooperative Extension

Garden Tips for May!

David Hillock

Trees and Shrubs
• Prune and feed azaleas immediately after blooming.
• Insect Alert: (EPP-7306)
* Bagworms on juniper and arborvitae. (Late May)
* Elm leaf beetles and larvae on elms. (Late May)
* Mimosa webworms on mimosa and honeylocust.
* Lace bugs on sycamore, pyracantha and azalea.
• Soak new transplants and newly planted trees unless rainfall is abundant.
• Pine needle disease treatments are needed in mid-May.

• Cool-season lawns can be fertilized again. If you did not fertilize cool-season grasses in March and April, do so now.
• Warm-season lawns may be fertilized again in May. (HLA-6420)
• Seeding of warm-season grasses such as bermudagrass, buffalograss, zoysiagrass and centipedegrass is best performed in mid-May through the end of June. The soil temperatures are warm enough for germination and adequate growing season is present to promote winter hardiness.
• Dollar spot disease of lawns can first become visible in mid-May. Make certain fertilizer applications have been adequate before ever applying a fungicide. (EPP-7658)
• Nutsedge plants become visible during this month. Post-emergent treatments are best applied for the first time this month. Make certain warm-season grasses have completed green-up.
• The second application of pre-emergent annual grass herbicides can be applied in late-May or early June, depending upon timing of first application. Check label for details.
• Vegetative establishment of warm-season grasses can continue. (HLA-6419)

• Annual bedding plants can be set out for summer color.
• Plant summer bulbs such as cannas, dahlias, elephant ear, caladiums and gladiolus.
• Shake a leaf over white paper to look for spider mites. If the tiny specks begin to crawl, mites are present.

Water Gardens
• Clean out water garden and prepare for season. Divide and repot water garden plants.
• Begin feeding fish when water temperatures are over 50°F.

Fruits and Vegetables
• Plant watermelon, cantaloupe, cucumber, eggplant, okra, sweet potatoes, etc.
• Fruit spray programs should be faithfully continued during the next several weeks.
• Late May is the best time to control borers in the orchard. Check for label recommendations and controls.

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