rough mannagrass
Glyceria maxima (Hartman) Holmb.


Reed mannagrass is a perennial, semi-aquatic, rhizomatous grass. Stems are unbranched and can reach 2-8.2 ft. (0.6-2.5 m) in height. Leaves are 12-23.6 in. (30-60 cm) long, 0.2-0.8 in. (6-20 mm) wide, with an acute apex and a prominent midrib. Flowering occurs in June-August, when flowers appear in 6-12 in. (15-30 cm) long panicles. This plant reproduces primarily vegetatively and occurs in sunny to semi-shady wetlands, where it can form dense impenetrable stands. Reed mannagrass is native to northern Eurasia and was first found in North America in 1940 on the edge of Lake Ontario.


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EDDMapS Distribution

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State Regulated List

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Liliopsida
Subclass: Commelinidae
Order: Cyperales
Family: Poaceae
Genus: Glyceria
Subject: Glyceria maxima (Hartman) Holmb.


Plants - Grass or Grasslike