Yellow nutsedge has been rearing its ugly head lately.
This weed looks like a grass and is sometimes incorrectly called nutgrass. Unlike grasses, however, nutsedge has triangular stems and three-ranked leaves, meaning the leaves come off the stem in three directions. Yellow nutsedge is pale green to yellow in color. It grows rapidly in the spring and early summer, and because of this rapid shoot growth, it sticks up above the rest of the lawn only a few days after mowing. This weed is a good indicator of poor drainage, but it can be introduced into well-drained sites through contaminated topsoil or nursery stock.
Nutsedge is difficult, if not impossible, to control culturally because it produces numerous tubers which give rise to new plants. Some degree of suppression -- gradually reducing the population or keeping it from spreading further -- may be achieved by improving drainage in the infested area and mowing frequently. For cool-season grasses, fertilizing with nitrogen in early November helps because nutsedge vigor is reduced by frost more than cool-season turfgrasses are.
Several chemical products are available with varying efficacy. Manage is a relatively new product which is very effective on yellow nutsedge and safe for most turfgrasses. This product has now been introduced in the homeowner market but is not widely available yet. Check with local suppliers to see if they carry it. Basagran (bentazon) is the next most effective yellow nutsedge herbicide, but it is primarily sold to commercial applicators. MSMA (monosodium acid methanearsonate) can also be used. MSMA is the least effective of the three and will require repeat applications. However, it is the least expensive and is widely available. It is often sold under generic names such as ``crabgrass killer'' and ``nutgrass killer.'' Check the label to determine if such products contain MSMA.
-- The Garden Calendar is sponsored by K-State Research and Extension-Douglas County office and written this week by Michelle Sinn, extension intern. For more information call the Master Gardener Hotline at 843-7058, between 1 p.m. and 4 p.m. Monday-Friday.