Scientific Name: Cyperus rotundus

Common Name: nutgrass

Other Common Names: chaguan humatag, cocograss, kili'o'opu,pakopako, purple nutsedge

Habit: Nutgrass is a perennial weed plant from rhizomes and tubers. It can reach 2 1/2 feet in height. It is found throughout the southeastern United States as a common weed of agronomic and horticultural crops, nurseries, turfgrass, and landscapes.

Leaves: The leaves are yellow to green in color with a distinct shiny appearance. Leaves are 5mm to 8 mm wide. They have a distinct ridge along the mid-vein. Leaves are without hairs and appear triangular in appearance. No auricles or ligules are present in Purple Nutsedge. The leaves of purple nutsedge taper abruptly to a very sharp point unlike those of yellow nutsedge which taper gradually to a point.

Identifying Characteristics: The success from this troublesome weed is due to its ability to survive and reproduce from tubers during adverse conditions. It grows in almost every soil type, over a wide range of soil moisture, pH and elevation. It can survive the highest temperatures encountered in agriculture.

Flower Seed Head: Purple Nutsedge spikelets occur at the ends of the solitary stems where the flower stalks arise from a common point. Individual spikelets are reddish-purple to reddish-brown in color.

Seed Fruit: Seed is linear to oblong about 1.5 mm long and 1 mm wide. It has a triangular cross section and is olive gray to black and has gray lines on it. Plant most often grows back from tubers.

Where Found: Purple Nutsedge is primarily found in the warm humid Southern United States.

  • Life cycle: perennial

  • Plant type: Sedge

  • Auricle: not present

  • Plant family: Cyperaceae

  • Leaf arrangement: folded in bud

  • Hair surface: no hairs

  • Ligule: none

  • Length: none

  • Root structure: fibrous; rhizomes present

  • Seed head: spike

  • Width: less than 5 mm; 6 to 15 mm

  • Grass stem: triangle