KTRH GardenLine Newsletter

Aug. 5, 2010 - Issue #172

Here's Randy's Weekly KTRH GardenLine Tip:

Nutgrass Control All Different Ways

Last Saturday, I was at The Woodlands Ace Hardware store, and you wouldn't believe the amount of weeds listeners brought in sealed plastic bags for me to look at. And nutsedges/nutgrasses had to be the dominant entry.

Nutsedges and nutgrasses are common turfgrass weeds that favor warm climates and poorly drained areas. Golf courses often provide ideal environments for several types of sedges. Some of the more common on golf courses include purple nutsedge, yellow nutsedge, globe sedge, rice flat sedge, annual sedge and kyllinga species. That's pronounced kuh-LING-uh.

In Southeast Texas, most of us are fairly certain about Nutsedge. But I get lots of calls and e-mails about a sedge that has the burrs on top, and that is kyllinga. Appropriately, four of the letters in kyllinga are "kyll" ... like KILL. And that's exactly what should be done to it.

Kyllinga species are becoming more prevalent on golf courses. Worldwide, there are 45 kyllinga species, but only five are currently found in the continental U.S. and one in Hawaii. Most are rather difficult to detect in turfgrass, because they closely resemble turf. Kyllinga leaves, however, are glossier than turfgrass and are spotted easier in the morning as dew falls off their leaves but remains on the turf. Also, kyllinga leaves have a distinctive "minty sweet" scent when mowed or crushed.

Kyllinga Identification
Green kyllinga (Kyllinga brevifolia) is the most commonly known turf weed of all kyllinga species. Green kyllinga has a rhizomatous/stoloniferous growth. Stolons (runners) intertwine within turf to produce thick mats. Repeated applications of herbicide (like Image, Basagran, MSMA, and Manage) are generally required to remove green kyllinga, because the herbicides only contact the outer surface. I have personally had great success with Manage. Mats generally begin small, however they may increase in size if unnoticed and can literally choke out the surrounding turfgrass.

Green kyllinga also produces viable seed throughout the growing season. Its seedheads are about the size of a garden pea when un-mowed and have a light green color. Seeds start germination in spring and continue throughout the summer.

But when you have it, you want to kill it, right? That's where post-emergent controls specifically designed for nutgrass/kyllinga come in to play. There are three readily available:
  • Sedgehammer by Gowan
  • Nutgrass 'Nihilator by Monterey
  • Image by Lily Miller

    I recommend Sedgehammer most because it can be used anytime of the year. Nutgrass 'Nihilator works, but it isn't as readily available. And Image is not safe to use in warmer months because it can damage the St. Augustine, when temperatures are 90 and above.

    The key to success in nutgrass control is to use a surfactant. If you aren't familiar with what I've written about surfactants, please read this tip sheet.

    There is also an "organic" way to treat for nutgrass, but it's very hit-and-miss. I've heard just as many "it didn't work" stories as I have success stories about using molasses. Usually, you mix ½ cup of agricultural molasses with one gallon of water. Here too, I would add a bit of surfactant to the mix. One issue with molasses, though: you may still see nutgrass blades in the turf. But it really does work on the "nut" part of the weed.

    Pre-emergent controls for grassy weeds, such as Betasan, Barricade, Pendimethlin and Dimension are very important for long-term control of sedges and especially kyllinga. See our lawn fertilization schedule.


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