Landscape activities pick up during April

By Bill Geer

Published: March 27, 2008

Q:Please list tips for the landscape I can use in April?

A:Here are some things to keep in mind for April.

•Don't spray insecticides during fruit tree bloom, or pollination may be affected. Disease sprays can continue according to schedule and label directions.

•Avoid using Sevin on apple trees until 30 days have passed from bloom or until fruit is near the size of a quarter.

•Control cedar-apple rust. When the orange jelly galls are visible on junipers (cedars) following a rain, begin treating apple and crabapple trees with a fungicide.

•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.

•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.

•Control of powdery mildew disease can be done with early detection and regular treatment. Many new plant cultivars are resistant.

•Leaf spot diseases can cause premature death of foliage and reduce plant vigor.

•Most bedding plants, summer flowering bulbs and annual flower seeds can be planted after the risk of frost passes. This happens around mid-April in most of Oklahoma.

•Hold off mulching these crops until spring rains subside and soil warms. Warm-season annuals should not be planted until soil temperatures are in the low 60s.

•Harden off transplants outside in partial protection from sun and wind before planting.

•Let spring flowering bulb foliage remain as long as possible before removing it.

•Wait for the weather to warm 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.

•Watch for cutworm damage and add flea beetle scouting to your list of activities in the vegetable garden.

•Hummingbirds arrive in Oklahoma in early April. Get your bird feeders ready using one part sugar to four parts water. Do not use red food coloring. Keep the bird feeder filled during 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 insect pests and predators. Some pests can be hand-picked 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 from sprigs, plugs or sod beginning in late April.

•Warm-season grasses can be fertilized four times per season using one pound of actual nitrogen per 1,000 square feet in each of four applications. Apply one pound in April, May, June and September. Water in nitrate fertilizers.

•Mowing of warm-season lawns can begin now. Cutting height for bermuda, buffalo and zoysia should be 1 to 1½ inches high.

•Damage from spring dead spot disease becomes visible in Bermuda grass. Perform practices that promote grass recovery. Do not spray fungicides at this time to control dead spots.

•Grub damage can be visible in lawns at this time. Check for the presence of grubs before applying any insecticide treatments.

•Apply appropriate soil insecticide if white grubs are a problem. Water product into soil.

Bill Geer is director of the Oklahoma County Extension Service. His column addresses frequently asked horticulture questions. For more information, call 713-1125.

Comments