P&PDL Picture of the Week for
May 30, 2005

Yellow Nutsedge Beginning to Show

Glenn Hardebeck, Turfgrass Research Agronomist, Department of Agronomy, Purdue University

Yellow nutsedge is beginning to show up in lawns across Indiana (Fig. 1 and 2).  This light green to yellow grass-like perennial weed begins to emerge during late May to early June in much of the state.  Yellow nutsedge (also called nutgrass or swampgrass) is neither a grass nor a broadleaf.  It is a true sedge and as such, it is not controlled with the usual weed killers.  Sedges can be differentiated from other grasses by their triangular stem, which can be easily felt by rolling the stem between your fingers (Fig. 3).

As with most weeds, control begins by promoting a vigorous, healthy stand of turf that can compete well against the yellow nutsedge.  If only a few yellow nutsedge plants are present, hand weeding may be successful.  If a wider area is infested, products containing MSMA or DSMA can be used to control yellow nutsedge.  Pay attention to label directions, because these products can injure the desirable turf as well.  Some garden centers offer the better choice of products for nutsedge control, which include halosulfuron (Manage) and bentazon (Basagran).  Reapplications are usually required for control.

Whether you attempt control through hand weeding or chemical applications, yellow nutsedge is a tough nut to crack due to its extensive underground root system and underground nutlets (tubers) which enable it to re-establish itself in a turf area.  Many times it requires multiple years and diligence to eradicate this problem from a turf area.  More information on yellow nutsedge control can be found in  AGRY-98-04: Control of Yellow Nutsedge in Homelawns.  

Click on image to enlarge

Fig 1: Yellow nutsedge growing fast in a turf stand

Fig 2: Yellow nutsedge is not a grass or a broadleaf

Fig 3: Roll the stem between your finger to feel the triangular stem

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service