Reed Canarygrass
Phalaris arundinacea
Washington State Classification
Class C — Widespread, County-Selected Control
It is a major threat to natural wetlands.
Quick Reference
Identification
Growth Habit
A highly variable species, reed canarygrass is a rhizomatous, perennial, cool season grass that can reach three to six feet in height. It forms dense monotypic stands in wetland ecosystems.
Leaves
Leaf blades are flat and hairless, 1/4 to 3/4 of an inch wide. Ligules 0.16 to 0.39 inch (4 to 10 mm) long.
Flowers
Flowers are densely clustered in panicles with 3 florets per spikelet, one floret is fertile while the other two are sterile. Plants bloom May to mid-June. They are green to purple and change to beige over time.
Impact
It is a major threat to natural wetlands. It out competes most native species as it forms large, single-species stands, outcompeting other species. Dense stands have little wildlife habitat value. Its invasion can cause siltation in irrigation ditches.
Ecology & Spread
Habitat
It typically occurs in soils that are saturated or nearly saturated for most of the growing season. Established stands can tolerate extended periods of inundation. It grows in roadside ditches, river dikes, shallow marshes, wetlands and meadows. Please click here to see a county level distribution map of reed canary grass in Washington.
Spread Mechanisms
Reproduction
Reed canarygrass can spread by seeds or by creeping rhizomes. The species will also produce roots and shoots from the nodes of freshly cut stems.
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Control Methods
Mechanical
- Mowing may be a valuable control method, since it removes seed heads before seed maturation and exposes the ground to light, which promotes the growth of native species. Studies in Wisconsin indicated that twice-yearly mowings (in early to mid-June and early October) led to increased numbers of native species in comparison to reed canarygrass-infested plots that were not mowed.