Good Lawn Practices Reduce Risk of Nutsedge Taking Over

Contact: Patrick Byers, horticulture specialist
Tel: (417) 881-8909

E-mail: byerspl@missouri.edu

SPRINGFIELD, Mo. -- Nutsedges are common weeds in landscapes and, once established, they can be extremely difficult to eliminate.

“Nutsedges thrive in waterlogged soil, and their presence often indicates drainage is poor, irrigation is too frequent, or sprinklers are leaky,” said Patrick Byers, horticulture specialist, University of Missouri Extension.

Although nutsedges resemble grasses and often are referred to as “nutgrass,” they aren’t grasses but are true sedges according to Byers.

Their leaves are thicker and stiffer than most grasses and are arranged in sets of three at their base. Nutsedge stems are solid, and in cross section they are triangular.

Yellow and purple nutsedges produce tubers on rhizomes, or underground stems that grow as deep as 8 to 14 inches below the soil surface. Buds on the tubers sprout and grow to form new plants and eventually form patches that can range up to 10 feet or more in diameter.

Yellow and purple nutsedges are perennial plants and the tubers can survive for up to three years.

“Nutsedges are a problem in lawns because they grow faster, have a more upright growth habit, and are a lighter green color than most grass species, resulting in a nonuniform turf,” said Byers.

In gardens and landscapes, nutsedges will emerge through bark or rock mulches in shrub plantings and vegetable and flower beds throughout the growing season.

“The best approach for avoiding nutsedge problems is to prevent establishment of the weed in the first place. Once established, nutsedge plants are difficult to control,” said Byers.

Prevent establishment by removing small plants before they develop tubers, eliminating the wet conditions that favor nutsedge growth, using certain fabric mulches in landscape beds, and making sure nutsedge tubers aren’t brought in with topsoil or other materials.

“Tubers are the key to nutsedge survival. If you can limit production of tubers, you’ll eventually control the nutsedge itself,” said Byers. “To limit tuber production, remove small nutsedge plants before they have 5 to 6 leaves; in summer this is about every two to three weeks.”

Continually removing shoots eventually depletes the energy reserves in the tuber. The best way to remove small plants is to pull them up by hand or to hand hoe. If you hoe, be sure to dig down at least 8 to 14 inches to remove the entire plant.

Few herbicides are effective at controlling nutsedge, either because of a lack of selectivity to other plants or a lack of uptake.

“Two that are recommended for home gardeners are sold under the names of Sedgehammer and Basagran T-O,” said Byers. “Some new products marketed specifically for nutsedge have come on the market this spring and can now be found at large retailers too.”

Many people mistakenly use Roundup on fully grown plants to try to kill the tubers.

Unfortunately, when tubers are mature the herbicide usually doesn’t move from the leaves to the tubers, leaving them unaffected, according to Byers.

For more information, contact the lawn and garden helpline operated by the Masters Gardeners of Greene County at (417) 881-8909.