Nutsedge (often called nutgrass) is a perennial grasslike weed that can be very hard to control in lawns and gardens. It produces a wide-bladed grasslike leaf. It is important to stress that this plant is a sedge and not a grass despite the similar appearance.
The unique characteristic that distinguishes nutsedge from grasses is that it has three leaves -- making the stem triangular. This is easy to observe just by feeling the stem with your fingers or by cutting the stem off with a knife and looking down on the cut surface: It will obviously be triangular.
Nutsedge is a warm season perennial weed -- growth doesn't start until the soil warms in May. Most plants grow from overwintered tubers germinated near the soil surface. Leaves emerge and a primary basal bulb is formed in the top 3/4 inch of soil. The bulb then grows a fibrous root system and produces rhizomes, secondary basal bulbs and then tubers (nutlets) at the end of the rhizomes. Nutlet formation begins in late June and continues until early fall. One plant can produce hundreds or even thousands of nutlets before the top of the plant dies in late summer or early fall. Each of these nutlets will grow into a new plant but not until they have gone through winter. Some nutlets can survive in the soil for several years until they are finally exposed to the right conditions for growth. Also, small seedheads are formed above the plant from July to September, and the seed also can be a source of seedlings. However, compared to the nutlets, seed is considered an insignificant means of reproduction.
There are no quick fixes in nutsedge control. Nothing will eliminate it in one easy treatment. Control should be based on a complete program that uses a variety of methods to attack the weed. The most important single ingredient is persistence. Roundup can be used to kill the tops of actively growing nutsedge, but does not kill the nutlets so they remain in the soil for the future. Also, Roundup kills all plants with which it comes in contact. A chemical called Manage is effective for nutsedge control. Apply at the three to 11 leaf stage of plant growth. Manage will kill the nutlet but it may take more than one application to eradicated the problem.
-- The Garden Calendar is sponsored by K-State Research and Extension-Douglas County Office and written this week by Master Gardener Deanne Lenhart. For more information call the Master Gardener Hotline, 843-7058, from 1 p.m. to 4 p.m., Monday through Friday.