Gardening tasks for April
The April list of garden tasks is taken from the OSU Extension Publication, HLA-6408 – Landscape Maintenance Schedule. This maintenance schedule is a checklist which emphasizes prevention rather than remediation. Some of the topics mentioned below have individual Fact sheets available at http://osufacts.okstate.edu.
Lawns
Warm-season grass lawns can be fertilized three to five times per season using one pound of actual nitrogen per 1,000 sq. ft. in each application. Apply one pound in April, May, June, August and September for a high-quality lawn. Water in nitrate fertilizers. (HLA-6420)
Mowing of warm-season grasses can begin now. Cutting height for Bermuda and zoysia should be 1 to ½ inches high. Mow buffalo at 3 inches high. (HLA-6420)
Damage from Spring Dead Spot Disease becomes visible in Bermuda grass. Perform practices that promote grass recovery. Do not spray fungicides at this time for SDS control. (EPP=7665)
Flowers and shrubs
Most bedding plants, summer/flowering bulbs and annual flower seeds can be planted after danger of frost. This happens around mid-April in most of Oklahoma.
Let spring flowering bulbs (daffodil, tulip, etc.) foliage remain as long as possible before removing it.
Fungicides for leaf spot diseases can be applied.
Control of powdery mildew disease can be done with early detection and regular treatment. Many new plant cultivars are resistant. (EPP-7617)
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.
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 degrees.
Trees and shrubs
Remove any winter-damaged branches or plants that have not begun to grow by late April. (HLA—6404)
Control cedar-apple rust. When the orange jelly galls are visible on juniper (cedar), begin treating apple and crabapple trees with a fungicide. Treat hawthorns accordingly. (EPP-7611)
Fire blight bacterial disease can be controlled at this time. Plant disease-resistant varieties to avoid diseases (EPP-7615)
Begin Diplodia tip blight fungicide applications at bud break.