Reed Sweetgrass
Glyceria maxima
Washington State Classification
Class A — Eradication Required Statewide
Reed sweetgrass is an aggressive aquatic weed that produces an extensive network of underground roots and rhizomes that can reach one meter deep.
Quick Reference
Identification
Growth Habit
Reed sweetgrass is a perennial, rhizomatous wetland grass, sometimes variegated in appearance, reaching a height of around 8 feet (2.5 meters) tall.
Leaves
Leaf blades are flat, shiny and lightly grooved by a prominent midvein. They are typically 8.6 to 11.4 inches long by 0.25 to 0.79 inches wide. Leaf margins have short stiff hairs. In the variegated variety, the blades are longitudinally striped.
Flowers
The flowers are arranged in a branching flower cluster, widest at the base. Typically flowers are produced during the spring and summer and consist of narrow spikelets that range from yellow to green with a purple tinge.
Fruit & Seeds
Seeds are small and dark brown.
Impact
Reed sweetgrass is an aggressive aquatic weed that produces an extensive network of underground roots and rhizomes that can reach one meter deep. It forms dense monotypic stands, crowding out native vegetation. It is a serious threat to our wetlands.
Ecology & Spread
Habitat
It typically grows along rivers, dams, streams and ponds. Please click here to see a county level distribution map of reed sweetgrass in Washington.
Spread Mechanisms
Reproduction
Sweet reedgrass reproduces by seed and by rhizomes.
"
Control Methods
Mechanical
- Small patches of sweet reedgrass can be dug up, as long as all the roots and rhizomes are removed. Large infestations may be excavated.
Biological Control
- .