Ministry of Agriculture, Food and Rural Affairs

Ontario Weeds: Quack grass

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Stems and Roots
6. Flowers and Fruit
7. Habitat
8. Related Links

Name: Quack grass, Agropyron repens (L.) Beauv.,

Other Names: AGGRE, chiendent, Couch grass, Quitch grass, Scutch grass, Twitch, Twitch grass, chiendent rampant, agropyron rampant, Elytrigia repens (L.) Nevski, Elymus repens (L.) Gould

Family: Grass Family (Gramineae)

General Description: Perennial, spreading by seed and by light-coloured underground stems (rhizomes). Rhizomes have nodes or joints and internodes, and hard, white, very sharp-pointed tips. They produce roots and branches from the nodes. Some branches turn upwards to emerge as leafy stems. Others continue growing and branching horizontally and expand the patch. Each internode is partly covered by a short, light brown, dry, scaly sheath. It is distinguished from Smooth brome by its slender, unbranched seed head (spike), the presence of auricles its split sheath, and its sharp-pointed light-coloured rhizomes with short scaly sheaths.

Photos and Pictures

Quack grass (A - plants in head; B - leaf-base showing auricles).

Quack grass

Quack grass. A. Non-flowering plant. B. Leaf-base. C. Spike. D. 1 Spikelet.

Stem and leaf-base characteristics of a typical grass.

Stems & Roots: Stems erect, 30-120 cm (1-4 ft) tall, either not flowering during the whole growing season or producing a slender, unbranched inflorescence called a spike; stem nodes (joints) distinct and often purplish. Leaves flat, nearly smooth; lower leaf sheaths hairy, upper ones often smooth, sheaths split with margins overlapping; auricles present and clasping the stem like little hooks. Spike (seed head) with 1 (rarely 2) unstalked spikelet at each node or joint.

Flowers & Fruit: Spikelets alternating from one side of the rachis (central stalk of the spike) to the other, and with their flat or broad side towards the rachis; each spikelet made up of 3 to 7 florets ("seeds") side by side between 2 outer glumes (empty chaff), and either with short awns (bristles) or awnless. Flowers from June to September.

Habitat: Quack grass occurs in cultivated fields, pastureland, waste places, rights-of-way, lawns and gardens in almost any soil texture throughout Ontario. This is the most troublesome perennial weedy grass in Ontario and throughout Canada.

Related Links

... on general Weed topics
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control

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