Quackgrass

Encyclopedia Article

Quackgrass                   Elymus repens (L.) Nevski

Family:  Poaceae
Life cycle: Perennial, reproducing by rhizomes and seed
Native status:  Native to Europe, introduced to North America in the 1600’s as a contaminant in hay and straw.
Habitat:  Crop fields, forages, turf.  Adapted to cool temperatures and more common in northern Iowa.

General description:   Early emerging erect plant typically found in small, distinct patches due to spread by rhizomes.  Sheaths and leaves may be hairy or smooth.  Plants can reach heights of 3 feet.  Spikelets (seeds) are arranged in two rows along the seedhead (2 to 6” in length).

Key ID traits:   Clasping auricles; short, membranous ligule; smooth rhizomes with long internodes.

Similar species:  Tall fescue and several ryegrasses (Lolium spp.) are frequently mistaken for quackgrass due to similar styles of seedheads; however, only quackgrass has long rhizomes.

Miscellaneous:  Quackgrass was a major weed of corn and alfalfa prior to systemic herbicides.  Applying 5 lbs of atrazine was the standard treatment in continuous corn. Specialized tillage tools called quack-diggers were developed that would drag rhizome to soil surface where they would dessicate.Since it was so difficult to manage in alfalfa, breeders at the University of Minnesota attempted to develop cultivated varieties that would have better forage quality.


Quackgrass is Iowa's only agronomic weed that has clasping auricles, ear-like projections that extend from base of leaf blade around the stem.


Quackgrass spreads by rhizomes, which are underground stems.  The introduction of glyphosate has minimized problems with this weed in ag fields.

 


The seedhead is a slender spike with two rows of seeds.

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