Reed Canarygrass

Phalaris arundinacea
Reed Canarygrass
Species distinguishing characteristics: 
  • Robust, hairless perennial grass that often grows in dense clumps in moist to wet soils
  • Greyish to bluish-green stems, up to 2 m tall
  • Narrowly triangular leaves with rough margins
  • Straw-colored to pinkish flowers in a dense cluster with short, erect branches        
  • Spikelets with 1 fertile and 2 sterile, hairy and scale-like florets
  • Shiny, straw-colored or golden brown seed heads
Family Characteristics: 
  • Flowering stems have nodes and are hollow and round in cross section
  • Alternate leaves sheath the stem on their lower portion and form a hairy or membranous scale (ligule) inside the base of the leaf sheath
  • Flower clusters of numerous spikelets that attach directly to the flowering stem (spike) or attach by small stalks and are often branched (panicle)
  • A pair of bracts, called glumes (the outer/lower one being larger), enclose spikelets at the base
  • Each spikelet has one or more florets (dry, single seed flower) surrounded by 2 bracts (a lower lemma and a smaller upper palea)
  • Lemmas and/or glumes may have needle-like, stiff hairs (awns)
  • Florets have 3 stamens (pollen organs) and 2 feathery stigmas (tip of the female organ for receiving pollen) but lack showy petals and sepals as they are wind pollinated
  • Fruit is a seed-like grain enclosed in the bracts (called chaff in cereal grains)
  • Well-known members of this family include cereal grains such as wheat (Triticum spp.), corn (Zea spp.), rice (Oryza spp.), and oats (Avena spp.)
Growth habitat: 

Robust, perennial grass, 50 cm to 2 m tall, from rhizomes.  Often grows in dense clumps or mat-like colonies that exclude other plant species in wet areas.  Although the species is native to North America, the introduction of invasive varieties from Eurasia and the hybridization of native varieties with these cultivars has likely eliminated most native strains.

Leaves and stems: 

Hairless stems and leaves.  Mostly erect, stout, coarse stems occasionally bend at the base.  Stems have leaves along their entire length with largest leaves often at the mid-stem.  Grayish green to bluish green, flat or slightly-keeled leaf blades, 6–17 mm wide and up to 35 cm long, are rough to touch and have a prominent mid-vein visible underneath.  The leaves have rough margins and are broad at the base, and narrowly triangular, tapering to a point and usually flopping downward toward the tips.  Leaf sheaths are purplish at the edges, and open around the stem, often overlapping.  The thin, transparent ligules, 4–10 mm long, are blunt or rounded with tips that usually turn backwards and are irregularly jagged.


Flower cluster is a pale green or straw-colored to purplish-pink, dense, narrow panicle, 7–25 cm long and 1–6 cm wide, with short, erect branches that spread during blooming (when yellow pollen sacks protrude out of the florets).  The compactness of the panicle makes it appear spike-like.  The compressed, flattened spikelets appear to have a single floret, but actually have 1 fertile upper floret and 2 sterile lower florets represented by slender, scale-like hairy lemmas, 1–1.5 mm long.  Each spikelet has 2 slightly unequal, 3-nerved glumes, 4–7 mm long, that are slightly rough on the keels and taper to a point at the tips.  The single shiny, tan fertile lemma, 3–4 mm long, is smooth or finely short-haired, has 5 nerves, and tapers to a point but lacks an awn.  The fertile lemma encloses a similar sized, 2-nerved palea.


Extensive, long, scaly, pinkish rhizomes.


Black seeds inside the shiny, hairy lemmas within golden brown or straw-colored seed heads that often shatter when touched.  “Weed-free” forage often contains reed canarygrass seeds.

Habitat preferences: 

Moist to wet soil (or shallow standing water) of wetlands, marshes, meadows, stream banks and shores, forests openings, thickets, and disturbed areas such as roadsides and ditches at low to subalpine elevations.  Prefers rich soil and full sun to partial shade.

Interesting facts: 

The name Phalaris is Greek for “shining” and refers to the shiny seeds, and the name arundinacea means “reed-like.”  Reed canarygrass is highly invasive and often dominates wetland areas where it is present due to its vigorous growth and seed production, resistance to drought, long growth period, and ability to thrive with disturbance.  Despite its invasiveness, it is still often planted for hay and silage feed production.  Some nurseries still sell cultivars including a variegated ornamental variety (forma variegata).  It can be controlled by the application of herbicide after burning or mowing the plant.

Some waterfowl (e.g. snow geese (Chen caerulescens), upland game birds (e.g. ring-necked pheasants (Phasianus colchicus)), songbirds (e.g. lazuli buntings (Passerina amoena) and American pipits (Anthus rubescens)), ungulates (e.g. moose (Alces alces) and elk (Cervus elaphus)), and small mammals (e.g. muskrats (Ondatra zibethicus) and voles (Microtus spp.)) use the foliage, as well as the seeds and roots to various extents, for forage.  The dense stands provide cover for these species as well as offer protection for breeding fish and amphibians.  Many of these species prefer native wetland grasses and reeds for forage and cover when they are available.  Livestock also graze the foliage before it becomes coarse and less nutritious at maturity.  Some strains of reed canarygrass may contain high concentrations of toxic alkaloids.

Native peoples soften dried reed canarygrass leaves by rubbing them, and stuffed mattresses and pillows with them or used them as insulation for clothing and moccasins.  The leaves were also woven into hats and mats.  The Salish peoples and other tribes used the stems for decorating baskets.  The green stems used to decorate baskets were cut, soaked in hot water, and bleached white by the sun.

Reed canarygrass is used contemporarily for water purification in reed bed systems that treat grey water or sewage effluent from municipal and industrial sources.

The high yielding ability of reed canarygrass that make it so problematic in wetlands, also lend to its potential for use as a cereal crop or as a source of biomass.

It has been used for erosion control and shoreline stabilization in the past, but this practice is discouraged as reed canarygrass dominates all other native species and reduces plant diversity and soil stability over time.

Biological Classification: