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An Assessment of Exotic Plant Species of Rocky Mountain National Park

Phalaris arundinacea L. (Phalaroides arundinacea)
Reed canary grass (Poaceae)

Current level of impact
Known locations in RMNP: unknown.

Origin: Considered a native to North America.
Geographic distribution: Found in western two-thirds of Colorado below 9000', throughout most of U.S. except southern states.
Ecological distribution: Along waterways and in meadows, wet prairies, stream banks and swales. Abundant along irrigation ditches, lower valleys, rivers and pond banks, and along drainage ditches.
Soils: Occurs on a variety of moisture conditions from wet to dry soils, does best on fertile and moist to wet soils. Also capable of surviving prolonged conditions of flooding and anoxic conditions.

Perennial, cool season, reproduces by seeds and stout creeping rhizomes. Large rhizomes are capable of forming bunches or continuous sods.
Seed dispersal: Ditches and waterways can serve as dispersal corridors.
Germination: Seeds germinate immediately after ripening. In greenhouse experiments, 95% of seeds germinated after harvest.

A very aggressive species that is highly competitive with other plants. Begins growth in early spring, grows vertically for 5-7 weeks, and then begins to spread laterally.
Level of impact: Poses a major threat to many wetland areas because of this plant's tenacity and rapid growth. Capable of invading areas dominated by perennial grasses (such as Agrostis alba or Festuca rubra) and can form dense monocultures. May inhibit growth of other species for 3-5 months, eventually eliminating these species.

New canary grass plants reestablish quickly from seeds when chemical and mechanical control methods are used.
Mechanical: Hand removal for control may be feasible for small stands. Some studies indicate that hand chopping the culms at flowering time may kill small clones. However, the strategy may be too labor intensive for controlling large stands.
Biological control: No biological control methods are known that are feasible for use in natural areas.
Chemical: No herbicides are selective enough to be used in high quality areas without the potential for injuring native species. In disturbed sites where there is not a concern for harming other native plants herbicides may be used. Rodeo (glyphosate) will kill reed canary grass when applied to foliage according to label specifications. Rodeo should be applied in early spring when most native wetland species are still dormant. The following spring, any surviving canary grass should be sprayed. Dalapon and Amitrol are also reported to control canary grass. Care should be taken to avoid contacting non-target plants. Seeding the treated areas with native grasses from the surrounding area as soon as the canary grass has died may also help to reestablish native species.
Other: Fire can help control the invasion and spread of reed canary grass in prairies with fire adapted species. These species out compete canary grass following the fire. However, fire is not effective in areas of dense monocultures of canary grass or where seeds or native plants are not present.

Notes: Used to be a common seed in birdseed mixes, but has since been replaced with a species of Panicum. Important constituent of hay from Montana to Wisconsin. Reed canary grass provides good forage prior to maturity and is useful for controlling erosion in wet areas. However, large populations of the plant can reduce the carrying capacity of irrigation and drainage areas.


Apfelbaum, S.l., and C.E. Sams. 1987. Ecology and control of reed canary grass. 
    (Phalaris arundinacea L.). Natural Areas Journal 7:69-70.

Hutchison, M. 1987. Vegetation management guideline: Reed canary grass (Phalaris 
    arundinacea L.). Natural Areas Journal 12 (3):159-160.

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