April Gardening Tips
Oklahoma Cooperative Extension Service, Division of Agricultural Sciences and Natural Resources
Department of Horticulture & Landscape Architecture, Oklahoma State University
David Hillock, Consumer Horticulturist
Fruit and Nut
- Control cedar-apple rust. When the orange jelly galls are visible on juniper (cedar), following a rain, begin treating apple and crabapple trees with a fungicide. (EPP-7319, EPP-7611)
- Fire blight bacterial disease can be controlled at this time. Plant disease-resistant varieties to avoid diseases.
- Continue spray schedules for disease-prone fruit and pine trees.
Tree and Shrub
- Proper watering of newly planted trees and shrubs often means the difference between success and replacement.
- Remove any winter-damaged branches or plants that have not begun to grow. Prune spring-flowering plants as soon as they are finished blooming. (HLA-6404, HLA-6409)
- Control of powdery mildew disease can be done with early detection and regular treatment. Many new plant cultivars are resistant. (EPP-7617)
- Leaf spot diseases can cause the premature death of foliage and reduce plant vigor.
- Most bedding plants, summer flowering bulbs, and annual flower seeds can be planted after the danger of frost. This happens around mid-April in most of Oklahoma. Hold off mulching these crops until spring rains subside and soil temperatures warm up. Warm-season annuals should not be planted until soil temperatures are in the low to mid-60s.
- Harden off transplants outside in partial protection from sun and wind prior to planting.
- Let spring-flowering bulb foliage remain as long as possible before removing it.
Landscape – General
- Hummingbirds arrive in Oklahoma in early April. Get your feeders ready using 1 part sugar to 4 parts water. Do not use red food coloring.
- Keep the bird feeder filled during the summer and help control insects at the same time.
- Lace bugs, aphids, spider mites, bagworms, etc. can start popping up in the landscape and garden later this month. Keep a close eye on all plants and use mechanical, cultural, and biological control options first.
- Be alert for both insect pests and predators. Some pests can be handpicked without using a pesticide. Do not spray if predators such as lady beetles are present. Spray only when there are too few predators to be effective.
- Warm-season grass lawns can be established beginning late April from sprigs, plugs or sod. (HLA-6419)
- Mowing of warm-season lawns can begin now (HLA-6420). Cutting height for Bermuda and zoysia should be 1 to 1½ inches high, and buffalograss 1½ to 3 inches high.
- Damage from Spring Dead Spot Disease (SDS) becomes visible in bermudagrass (EPP‑7665). Perform practices that promote grass recovery. Do not spray fungicides at this time for SDS control.
- Wait a little longer for it to warm up before planting cucurbit crops and okra.
- Plant vegetable crops in successive plantings to ensure a steady supply of produce rather than harvesting all at once.
- Cover cucurbit crops with a floating row cover to keep out insect pests. Remove during bloom time.
- Watch for cutworm damage and add flea beetle scouting to your list of activities in the vegetable garden.