Ahhh… summer. The ‘official’ start to summer is June 21, but you can bet we have already felt those summer temperatures. The start of summer is more than just about barbecue and popsicles, its also an important date to keep in mind if you are controlling yellow nutsedge.
Yellow nutsedge is a grass-like weed that is common in turf. It gets its name from the yellowish-green color of its foliage. Yellow nutsedge is a perennial weed that has a triangular stem and its flowers are little spikelet. The leaf blades always seem to grow faster than the surrounding grass, sticking up above the turf only a day or two after mowing. The root system is shallow and fibrous, often producing small nut-like tubers that serve as food storage organs. These small tubers will sprout and form new plants. The plants also spread by rhizomes, or root-like underground stems, which enables it to move rapidly throughout a lawn or landscape.
Controlling yellow nutsedge can be difficult. Regardless of the method, it is most effective if you try to control this weed before June 21 (the official start of summer). After June 21, or the longest day of the year, nutsedge tubers are now mature and will sprout and result in new plants and adding to your nutsedge problem.
There are several control measures to consider. Pulling the weed is effective, but you have to remain vigilant remove plants regularly. In areas of heavy yellow nutsedge infestation, chemical control may be needed. Common grass and broadleaf herbicides will not control yellow nutsedge. Specialized herbicides for controlling sedges must be used. There are a couple herbicide currently available for yellow nutsedge control including products that contain halosulfuron, like Sedgehammer, and sulfentrazone, like Sedge Ender. Two or more application of herbicide will normally be needed to provide control.
Nutsedge located in a flowerbed might need a different approach. Not all products can be safely used around flowers, so read the label on the sedge specific products. Another option in a flower bed or among other ornamentals is to spot treat with a glyphosate-containing product like Roundup. Carefully spray or use a paint brush to dab glyphosate on the nutsedge without getting it on your ornamentals will provide control.
When using any herbicide, carefully read and follow the label directions. When applying herbicides, avoid mowing about three days before treatment to be sure there is plenty of leaf surface area to adsorb the herbicide. Also, to ensure adequate herbicide absorption, do not water the lawn for at least 24 hours after you apply the herbicide.
Applications should be initiated as soon as you spot young, actively growing nutsedge plants. This is when it is most sensitive to herbicidal control and before nutlets have formed on the roots of new plants. Once this weed matures or nutlets have formed, control is more difficult regardless of the treatment schedule.
With a little work now you can control the yellow nutsedge and still have enough time to enjoy that popsicle.
Elizabeth Exstrom is the Horticulture Extension Educator with Nebraska Extension in Hall County. For more information contact Elizabeth at firstname.lastname@example.org, her blog at https://huskerhort.com/, or HuskerHort on Facebook and Twitter.