Controlling Nutsedge
In the St. Louis area, as well as around the world, a species of weed known as nutsedge (
Cyperus) is actually listed as one of the world’s worst weed problems, not just in turf and landscape, but on those acres where crops are produced. Here in the Midwest, where our soil actually freezes in the winter, the problem species is yellow nutsedge (
Cyperus esculentus).
It has proven to be very, very difficult to control, in both turf and landscape settings. There is a second, and even tougher, more aggressive species in the south, called purple nutsedge (
Cyperus rotundus).
While you may not know this weed by the name of “nutsedge” you might call it by a few of its other common names, such as “nutgrass”, “water grass” and even "inch-a-day.” Those are just the names we can print! Yellow nutsedge is a prolific perennial weed, and it is capable of producing tons (Literally! Tons!) of underground tubers, which look like miniature potatoes, typically the size of a moist pea. In addition to the true botanical tuber (the “nut”), nutsedge can reproduce and spread by additional types of vegetative tissues, especially rhizomes and stolons. The seeds are fertile, but believe it or not, they’re really not that important in the spread of this troublesome weed.
The lesson in botany really doesn't matter...it just makes nutsedge one of the toughest weeds of all to control. It's actually better to use herbicides to control this weed than it is to pull it. Here’s why…when you pull this plant, you're leaving behind tiny pieces of roots, tubers, rhizomes and stolons, all of which will regenerate an even thicker patch of sedge. The tuber of this nasty weed is in essence nothing more than a giant seed and it can come up from deep within the soil.
Without a doubt, the best herbicide for control of nutsedge in turf is
halosulfuron, sold as the SedgeHammer
®+ (Gowan Company). You’ll do a far
better job of killing the underground tissues by using halosulfuron,
because the active ingredient rapidly moves downward from the leaves into
the root system, where it will destroy a great deal of the underground
biomass (
Buy SedgeHammer®+ Now). Incidentally, glyphosate, the active
ingredient in Roundup
® brand herbicides, is only an “average” herbicide
for control of yellow nutsedge, and it’s not as effective as halosulfuron.
The real beauty of halosulfuron is its safety to turfgrass species. As
long as you use it according to label directions, and as long as you don’t
apply it when your turf is under significant stress (especially
temperatures above 92
oF), you shouldn’t cause any injury to your
turfgrass.
Spray this weed! Don't pull it! And sorry to break the news to you, but you should plan on spraying at least twice through the summer. Heavy infestations may take three applications each season. A hot summer will cause worse infestations of nutsedge than a cool summer. Effective control requires an application of SedgeHammer
®+ when the weeds become a visible nuisance in turf, typically in June, when the daily temperatures get hot. If we have a quick start to the summer heat, the nutsedge will pop earlier, too. If you give nutsedge even a few weeks of respite, it will quickly establish an entirely new set of underground tubers and rhizomes. This weed will come back every year, so just be sure not to let your guard down. If you do a good job it will become thinner and less invasive each year. Nutsedge likes full sun, wet soils, and hot temperatures. When our cool season turf gets stressed from heat (generally anything above 95
oF) it quits growing. But, nutsedge can grow in temperatures well above 100
oF. This is when it is typically most obvious…turf isn’t growing, while the sedge is very happy. Nutsedge detests shade, even the little bit of shade and competition created by a vigorous sward. If your turf has suffered from either disease or insect damage, or both, you’ll have noticed how rapidly the nutsedge filled in those weak areas. Many customers wonder where the nutsedge comes from in the first place. Nutsedge tubers often times come free when you purchase sod and topsoil! It will indeed encroach from your neighbor’s “pasture” so be sure to shame him/her if they don’t keep their weeds within their borders!
Here are a couple of fun facts about nutsedge:
- Yellow nutsedge is actually an edible food source.
- In tropical climates it's called "chufa", but the tubers are larger (marble sized) than they are here in St. Louis (pea-sized).
- If you like water chestnuts, you're eating tubers from the sedge family.
The best defense against nutsedge is a thick, healthy turf, so follow the advice offered below by
THE Turf Plan® to combine cultural control techniques along with your herbicide program.
Control of Nutsedge with SedgeHammer®+ using a Hand-Can or Small Sprayer
- Open the box of SedgeHammer®+, then the package holding the active ingredient plus surfactant.
- Add the contents of the package to warm/hot water when using a hose-end sprayer. Be sure to fill the sprayer to the 2 gallon mark, if your intent is to spray 1,000 to 2,000 sq ft. It’s OK to use a higher spray volume when using a hose-end sprayer (say 3 gallons) but it’s not prudent to use try to apply SedgeHammer®+ via a hose-end sprayer in less than 2 gallons of water.
- If you're using SedgeHammer®+ don't add anything else to the sprayer. If you're not using SedgeHammer®+, add a package of Kalo® DRI nonionic surfactant, and stir. Be sure the material is dissolved before you start spraying.
- This spray solution (2 gallons) containing SedgeHammer®+ can cover between 1,000 and 2,000 sq ft of infested turf.
- Do not soak the nutsedge patches – one pass, or a maximum of two passes, with the spray wand, over the patch should be sufficient. Do not spray to wet! While SedgeHammer®+ has excellent turf safety, an over-application can cause turf injury!
- If you have left over liquid, kill the nutsedge in your neighborhood. This product will not last very long once mixed. Maybe 2 to 3 days, but certainly no longer than that.
- Do not contact the foliage of desirable plants, but if you do, it’s not as unforgiving as glyphosate products. If you do accidentally make contact with foliage of ornamental plants, wash with fresh water, as quickly as possible.
- If you’re very careful, you can “dribble” the spray solution into the whorl of the nutsedge plants that are scattered in your landscape beds. The whorl of nutsedge actually has a small “reservoir” and a few strategically-placed drops are marvelously effective.
- It’s best to spray nutsedge ~2 days after mowing, when it’s easy to detect amongst the turfgrass. Wait at least one day before mowing or watering after application. We like to spray in the evening when the neon-green coloration is easier to detect.
- Death is slow. Nutsedge won’t die completely for 21 to 25 days, but it won’t regrow after the first mowing following application. If you notice regrowth 3 to 7 days after spraying, it’s most likely that you missed that patch, or sprayed too lightly.
- This product does not kill any other significant lawn and garden weeds, so you needn’t waste time spraying them. You can spray SedgeHammer®+ along with any broadleaf product, too.
Control of Nutsedge with SedgeHammer®+ using Hose-End Sprayer
- Open the box of SedgeHammer®+, then the foil envelope to get access to the small sack of water soluble packaging containing the granules.
- Drop the water soluble “baggie” into the sprayer, and be sure to use hot water when using a hose-end sprayer. Be sure to fill the sprayer to the 2 gallon mark, if your intent is to spray 1,000 to 2,000 sq ft. It’s OK to use a higher spray volume when using a hose-end sprayer (say 3 gallons) but it’s not prudent to use try to apply SedgeHammer®+ via a hose-end sprayer in less than 2 gallons of water.
- After you’re sure the granules and water soluble bag have dissolved, add a package of Kalo DRI™ nonionic surfactant, and stir. A good surfactant helps increase the effectiveness of SedgeHammer®+ on nutsedge.
- This spray solution (2 gallons) containing SedgeHammer®+ can cover between 1,000 and 2,000 sq ft of infested turf. As you’re moving about your lawn, dragging your hose behind you, be sure to keep the spray solution in the sprayer agitated. A wife is usually very effective at helping you achieve this “state.”
- Do not soak the nutsedge patches – make only one pass, or a maximum of two passes, with the sprayer pattern over each patch of nutsedge.
- If you have left over liquid, kill the nutsedge in your neighborhood. This product will not last very long once mixed. Maybe 2 to 3 days, but certainly no longer than that.
- Do not contact the foliage of desirable plants, but if you do, it’s not as unforgiving as glyphosate products. If you do accidentally make contact with foliage of ornamental plants, wash with fresh water, as quickly as possible.
- It’s best to spray nutsedge ~2 days after mowing, when it’s easy to detect amongst the turfgrass. Wait at least one day before mowing or watering after application. We like to spray in the evening when the neon-green coloration is easier to detect.
- Death is slow. Nutsedge won’t die completely for 21 to 25 days, but it won’t regrow after the first mowing following application. If you notice regrowth 3 to 7 days after spraying, it’s most likely that you missed that patch, or sprayed too lightly.
- This product does not kill any other significant lawn and garden weeds, so you needn’t waste time spraying them. You can spray SedgeHammer®+ along with any broadleaf product, too.
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Controlling Nutsedge
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Know Your Sward Size
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