Habitat: Common reed can be found in the floodplain and emergent plant community. It occurs along the border of lakes, ponds, and rivers, in tidal and non-tidal brackish and freshwater marsh communities, roadsides, and disturbed areas. It does not tolerate rapidly moving water.
Description: Common reed is an extremely tall (2-5 m) stout grass that grows in dense stands. The hollow stems are up to 2 cm in diameter. The leaves are greyish-green, flat, 15-40 cm long, 2-4 cm wide at the base, and gradually taper to a point. The large greyish-purple plumes, 15-40 cm long, bloom from late July to September. Each tiny flower is surrounded by silky hairs, giving the inflorescence its feathery appearance. As seeds mature, the purple plume turns into a coarse, furry, brown tassel.
Origin and Range: In New Brunswick, common reed occurs as both a native plant (Phragmites australis) and an introduced invasive one. The origin of the invasive subspecies, which has become widespread in North America, is unclear. In New Brunswick, the native subspecies is mainly found in coastal brackish marshes, although it does occur inland as well. Most inland populations found in disturbed areas are of the introduced invasive subspecies.
Annual Cycle: Common reed is an invasive perennial grass species that reproduces through the dispersal of seeds or creeping rhizomes (root-like underground stems). It is dormant throughout the winter, with germination taking place from April-May and primary vegetative growth occurring in June-July. Flowering occurs from late July to September.
Look Alikes: The native and non-native subspecies can be difficult to distinguish from each other. Generally, the non-native form emerges earlier in the season and continues to grow later in the fall. It is considerably more robust (e.g., more rigid stems) and grows in dense stands that exclude other species. The leaves of the native common reed are yellow-green while leaves of the introduced invasive are dark green/ grey. The stems of native common reed often have noticeable reddish bands in their lower half and are smooth and shiny as if polished, while stems of introduced invasive ones are dull, rough, and ribbed (ridges visible with the naked eye once leaf sheath has been removed).
Impact: Common reed can rapidly form dense stands of stems which can lead to a loss in biodiversity and species richness, loss of habitat, changes in hydrology, changes in nutrient cycling, an increase in fire hazard, and economic and social impacts by affecting property values and raising aesthetic concerns.