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Ministry of Agriculture

Yellow & Purple Nutsedge
WEED ALERT

Yellow Nutsedge
(Cyperus esculentus)

Purple Nutsedge
(Cyperus rotundus)

Family: Sedge

Other Names: Nutgrass

Description:
Yellow and purple nutsedge are both grass-like in appearance but have triangular stems in cross section. Both are aggressive perennials with much branched fibrous roots, rhizomes, tubers, bulbs and flowers borne in umbrella-like clusters at the end of flowering stems. Leaves are mostly basal, linear in shape with a prominent mid-rib.


Yellow Nutsedge flower cluster above long leaf-like bracts

yellow nutsedge image
Mature Yellow Nutsedge


Yellow nutsedge

Purple nutsedge

Height:
  • 1/2 to 2 1/2 feet tall
  • 1 to 2 feet tall
Stems:
  • as long as or shorter than basal leaves
  • longer than basal leaves
Leaves:
  • gradually taper to point
  • abruptly taper to point
Flowers:
  • yellowish-brown
  • leaf-like bracts under flower cluster are longer than flowers
  • purple to brown
  • leaf-like bracts under flower cluster are shorter than flowers
Tubers:
  • smooth, round at ends of some rhizomes
  • sweet almond flavour
  • rough, oblong,
  • irregularly shaped
  • connected in chains
  • bitter flavour

purple nutsedge image Mature Purple Nutsedge
nutlets image Purple Nutsedge Nutlets, Roots and Rhizome

Concern:

Yellow nutsedge is native to North America but is spreading to cause concern in agricultural crops in coastal B.C. Purple nutsedge, a native of Eurasia, is not yet known to be established in B.C. but was proven to have been introduced in 1996 with roses imported from Arizona. The nutsedges are classed among the worlds worst weeds due to the difficulty in controlling the tubers or "nuts" produced on the rhizomes. A single plant can produce several thousand tubers per season. These can remain dormant in the soil for extended periods and produce new shoots throughout the growing season.

What Can You Do?

  • learn to IDENTIFY yellow and purple nutsedge or take suspect plants to the Ministry of Agriculture and Food to confirm identification.
  • DON'T PLANT ornamental material containing suspect tubers
  • CONTROL outbreaks EARLY. IMPLEMENT an integrated control program including use of tillage, mulching, competitive cropping, herbicides and crop rotation. For field size infestations it is important that tillage be done in a manner that will not spread tubers to clean areas. CLEAN equipment prior to use on non-infested sites. DON'T rely on "one-shot" weed control. It won't work. Dormant tubers require a long term effort to control.
  • BE AWARE. Although the nutsedges are grass-like in appearance they are not grasses and will not be controlled by some of the common grass control herbicides.
  • DO NOT HESITATE. Control new infestations IMMEDIATELY.