Thursday, June 20, 2013

Yellow Nutsedge in Turf

Kevin W. Frank
Assoc. Professor & Extension Turf Specialist

While mowing my own patch of green last evening I noticed that one of my peskiest weeds has reappeared, yellow nutsedge (Cyperus esculentus).  I always find it helpful to look back through my records to see what I’ve written about in past years and what I perceived to be big problems.  After perusing my files I found references to nutsedge being particularly troublesome in 2000 and 2004.  Without pouring over historical weather data, both of these summers were recorded in my files as being cool, wet summers, just like the beginning of this season.  Only time will tell if 2013 becomes another ‘nutsedge year’.       

Yellow nutsedge is often called nutgrass or swampgrass.  It’s not a broadleaf, it’s not a grass, it’s a sedge and is easily identified by the triangular shape of the stem.  If you roll the stem between your fingers you should be able to feel the triangular shape of the stem.  Other distinguishing characteristics of yellow nutsedge include leaves that are light green to yellowish in color and waxy or slick to the touch.  Yellow nutsedge grows rapidly and the leaves are often seen several inches above the turfgrass canopy, similar to what is often seen with quackgrass.  Nutsedge produces tubers or nutlets underground that really make controlling this weed difficult.  These tubers can remain dormant in the soil for several years and sprout new plants when moisture becomes available.

Yellow nutsedge in a Kentucky bluegrass lawn.

 What are the options for controlling nutsedge in turf?  The first step, which has been challenging this year, is to keep up on your mowing schedule to prevent seed production, even though by most accounts seed is unlikely to germinate.  Hand weeding may be effective in a mulch bed but in turfgrass is a very difficult task. If you don’t get the underground tuber when you pull, you’ll be pulling again shortly. For the serious infestations a herbicide application may be necessary. 

Control options for the homeowner are somewhat limited, look for herbicides with the active ingredients sulfentrazone or halosulfuron.  Control options for professional applicators are more diverse.  In addition to the standby’s sulfentrazone and halosulfuron, mesotrione and a new herbicide Celero with the active ingredient idosulfuron provide control.  For serious infestations repeat applications over several years will likely be required to achieve complete control, remember all those nutlets resting under the surface waiting to grow new plants next year. 

Always read, understand, and follow the label directions. Mention or exclusion of specific products does not represent an endorsement or condemnation of any product by Michigan State University.  

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