Yellow Nutsedge

Yellow nutsedge, Cyperus esculentus, is a common lawn and garden weed in Missouri. It is also referred to as nutgrass or watergrass. It is not a grass but rather a sedge. This is evident in the stem that is triangular in cross section, not round as in grasses. The leaves are bright green and have a waxy appearance. It grows faster than many lawn grasses so it is often noticed when it outgrows the surrounding grass. It will also remain a bright green in summer when surrounding lawn grass may be a lighter green. It thrives in low spots and high moisture areas that drain poorly, but can occur in drier sites as well. The plant produces feathery, umbrella-like flower clusters. The plant is perennial, reproducing by seed and underground tubers. The underground tubers or nutlets can remain dormant in the ground for several years.

Integrated Pest Management Strategies

In Lawns

1. Pulling the plants when they are young can give temporary control. Pull young plant when they are young in late spring to early summer before they begin forming new tubers mid summer through fall. Pulling will not, however, remove the underground nutlets so it is not a cure. Dormant tubers can survive in the soil for up to 3 years and will require regular pulling to prevent new tubers from being formed. Increasing the health of the lawn by mowing high, aerating, and fertilizing in the fall can help the grass better compete with nutsedge. Be sure to remove plants in the lawn and adjacent areas before they go to seed. Warm-season grasses compete better with nutsedge than cool-season grasses.

2. Improve the health of the lawn. Improving the health of the lawn can better help it compete with germinating nutsedge. 

3. Treat with an herbicide. Herbicides specifically labeled for sedge control or with active ingredients such as sulfentrazone or halosulfuron provide effective control. Timing of application is important. Treat beginning in late spring to early summer to kill plants before they begin forming new tubers, which occurs summer through fall. Nutsedge can be a challenging weed to manage, and repeat applications may be required. Follow label directions for additional applications, if needed. 

In Planting Beds

1. Dig plants. In planting beds, dig nutsedge plants and remove the underground nutlets. Regular pulling will be necessary to effect control.

2. Spot treat with a herbicide. Spot treatment with an non-selective herbicide gives good control. Keep in mind that nonselective herbicides will injure most plants it comes in contact with. Use care around desirable plants.  

Organic Strategies

In lawns:  Strategy 1 is a strictly organic approach.

In planting beds:  Strategy 1 is a strictly organic approach.