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Rough mannagrass (Glyceria maxima)

Rough mannagrass Common Names: Reed mannagrass, tall mannagrass, reed sweet grass

Description: Can be distinguished from similar natives by its height as it grows up to 2.5 m (8 ft) tall.

Habit: Herbaceous, semi-aquatic, rhizomatous, perennial grass, grows up to 8.25 ft in height.

Leaves: 30-60 cm (12-23.6 in) long, 6-20 mm (0.2-0.8 in) wide, acute apex, prominent midrib, margins have stiff, short hairs. The leaf sheaths are rough in texture with a reddish-brown band at the leaf junction.

Stems: Unbranched; can reach a height of 2.5 m (8 ft).

Flowers: Inflorescence and open panicle, 15-30 cm (6-12 in) long, short, stiff hairs, spikelets are 5-8 mm (0.2-0.3 in) long; blooms June to August.

Fruit and seeds: Small seeds are 1.5-2 mm (0.07 in.) long, obovoid in shape and smooth in texture.

Habitat: Native to Eurasia. Found in open wetlands including marsh, meadow and shrub-carr, tolerate light shade.

Reproduction: Vegetatively by rhizomes and also by seed although little seed appears to be produced.

Similar species: American mannagrass (Glyceria grandis).

Monitoring and rapid response: Hand-pulling, making sure all parts of the root system are removed; effectively controlled using any of the several readily available general use herbicides such as 3% glyphosate, cuttings, drowning cut stubble.

Credits: The information provided in this factsheet was gathered from and the Michigan Natural Features Inventory.

Individual species images that appear with a number in a black box are courtesy of the network ( photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (

Common Name:

Rough mannagrass

Scientific Name:

Glyceria maxima







USDA Symbol:


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