Description:
Glyceria maxima (Poaceae -- the grass family) is a perennial, rhizomatous
grass. Stems are unbranched and can grow up to 2.5 m high.
Leaf sheaths have prominent midribs, visible transverse veins,
and are closed to near the top. The unlobed, membranous ligules
are 5-7 mm long, smooth and obtuse in shape. Leaf blades
are flat, 22-29 cm long and 0.7-2 cm wide. The leaf blades
are shallowly grooved, with prominent midribs. The leaf margins
have short, stiff hairs that are rough to the touch. The
plants are bisexual. The inflorescence is a panicle. The
inflorescence can be open (chasmogamous) or contracted and
symmetrical. The inflorescence branches have short, stiff
hairs similar to those on the leaf margins.
Glyceria maxima
has the ability to form huge stands in wetlands. It is an aggressive
plant that has been invasive in Ontario for over 50 years. Even
in its native range, conservationists are concerned with the
ability of reed sweetgrass to form monocultures under different
levels of disturbance. Reed sweetgrass has a competitive advantage
because growth starts early in the spring. Glyceria maxima reduces
plant species diversity in particular, seed producing plants
that provide food for wildlife. Glyceria maxima is a poor food-plant
and nesting substrate for wetland wildlife. G. maxima has
been used as a forage crop. However, several instances of cattle
poisoning have occurred due to cyanide production in the young
shoots.
- Mechanical: If
removing G. maxima by hand, concentrate on removing all pieces
of the root or resprouting may occur.
Black plastic used to smother the grass was 100% effective
in Massachusetts. However, this method is not feasible over large
areas.
- Biological:
Unknown.
- Herbicide:
A 3% solution of glyphosate (Rodeo) during early summer and late
summer months has been effective. Follow-up treatments the
year after application is recommended
For More Information:
Detailed information about reed
sweetgrass is available at the Washington
State Noxious Weed Control Board Web Site. |
