Joan Swenson: Best you can do with nutgrass is manage it
| Thursday, Apr 02 2009 01:41 PM
Last Updated Thursday, Apr 02 2009 01:41 PM
Hugh Smith wrote to ask what to do about nutgrass, the wickedest weed in a Bakersfield yard.
Nutgrass is a perennial weed that spreads by underground rhizomes as well as by "nuts" produced underground and while it will produce seed, according to materials I've read, reproduction of plants by seed is limited. Pre-emergent herbicides don't stop nutgrass, which dies back in the winter, and you can't easily block it by mulching or using weedcloth, because it can poke right through.
Nutgrass control is about management, physical and chemical. To keep it controlled, you should regularly and persistently remove plants or use a special herbicide designed to kill nutgrass.
Some background: Nutgrass is not a grass, but a type of sedge and comes in "yellow" or "purple" varieties. It loves wet soil, but once established it can survive with fairly little water. Out in the sun, in flowerbeds or lawns, it does fantastically, but it becomes thin and weak in dense shade areas.
To reduce the spread of nutgrass, get to work removing plants before they have five to six leaves. Regularly removing the plant depletes its energy. Be persistent, because the mature nuts can sprout new leaves up to a dozen times. Even better, try to get the nut, which can be a foot or deeper in the soil. When I remove nutgrass, I use a weeding tool to lift and loosen the soil below the plant while holding the plant with my other hand.
I have heard from gardeners who have been successful at using Roundup on plants with only two or three leaves. Apply when the weather is hot and dry and when the leaves have not been trimmed; do not get the chemical on any other plants.
Digging up nutgrass or applying Roundup is extremely difficult to do in lawns, however, which is where other chemicals come into play.
Gowan Co. produces the chemical called SedgeHammer (formerly by Monsanto, then called Manage) that can be used in lawns on yellow and purple nutgrass. The product is available at specialty yard care chemical suppliers such as Abate-A-Weed and Gardener's Supply. Dilute a package of SledgeHammer in water to spray 1,000 square feet of nutgrass. Adding a non-ionic surfactant, a soapy product, will make the chemical "wetter" and help it attach to slick nutgrass leaves. If you treat nutgrass with SedgeHammer, you may have to apply it four or five times during the warm weather nutgrass season. Treat before plants have five leaves. Another product, Nutgrass 'Nihilator by Monterey may also be effective; it is labeled to kill yellow nutsedge (rather than purple nutsedge) which is found throughout California.
Citrus tasting
Bill Heisey from Four Winds Citrus Nursery will be at White Forest Nursery, 300 Morning Drive, from 9 a.m. to 4:30 p.m. today with citrus varieties available for tasting. This show will include varieties that are not typically available for tasting, including Gold Nugget mandarin, Lane Late Navel orange, Midknight Valencia orange and Murcott mandarin. There will be several other varieties available as well.
Heisey will answer questions about citrus varieties and provide cultural tips. White Forest owner Jere White says tasting the fruit in advance of buying a tree and save money -- you know you'll like the fruit you're planting.
Newspapers as mulch
A caller asked if gardeners can use newspapers as mulch for flowerbeds and if water and fertilizer pass through the paper. People generally use newspapers in areas where they want to block sunlight and water from the soil, to stop weeds from growing. I've seen a thick pad of papers, six or so sheets, laid down and a thick layer of wood chips or something similar added on top to keep the newspapers from blowing away. One would generally avoid watering the area, too, except directly around shrubs. The newspapers would probably prevent water from reaching the soil easily and waste water intended for plants, although I believe newspapers would keep the soil beneath cooler and prevent evaporation of water. I don't think fertilizer would penetrate.
