Species: Cyperus esculentus (Yellow nutsedge)
Flower: Spikelets, straw-colored to gold brown
Native to: Northern Hemisphere, warm temperate to subtropical
Type of weed: sedge
GreenGrass treats with: post-emergent
Over the counter: post-emergent products containing halosulfuron or penoxsulam - read directions carefully, as it may take multiple applications. NOTE: Always read the product label to see what it controls, what you can put it on, and how to apply it.
Nutsedge is a very invasive summer perennial weed, not only in lawns and flowerbeds, but also in crops. Some call it nut grass because the underground tuber looks like a nut, although it isn't. Others call it water grass because excessive rainfall or poor drainage will always worsen a nutsedge problem. Nutsedge grows from a tuber in the ground and spreads by underground rhizomes, making a very complex and layered root system. Although we can smother the foliage in lawns, we may never completely eradicate it. The wetter the season, the more it will show up. You'll also find it in thin turf or bare areas.
Nutsedge can be a nightmare in flowerbeds, since flowerbeds are usually watered more. A good layer of mulch can help suppress it, or at least make it easier to pull. However, since nutsedge has such a great root system, you will rarely, if ever, get the whole root when you pull it. There are some pre-emergents for nutsedge, but they don't last a full season.
Yellow nutsedge is the most prevalent type of nutsedge here in Oklahoma. There is also a purple nutsedge (Cyperus rotundus), which is native to Africa, parts of Europe and southern Asia, but is now found almost worldwide, as is yellow nutsedge. The best way to tell the difference between the two is that the yellow nutsedge leaf is skinnier at the top, coming to a very slender point, whereas the purple nutsedge is wider and not as slender at the top. Sometimes a product will work better on one or the other, so read the label to see which type it's labeled for.
Trivia: Nutsedge is one of the oldest cultivated plants in Eqypt - they used it to make cakes. The tubers are still used as food in many cultures - called chufa or tiger nuts, they are rich in unsaturated fatty acids similar to olives.
The tubers of nutsedge contain from 20% to 36% oil and have been discussed as a potential crop for biodiesel.
In the UK, they soak the nuts, boil them, and let them ferment. Apparently, after preparation, they're pretty good carp bait!