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Glyceria grandis (American mannagrass)
Smith, R.W.

Glyceria grandis

Glyceria grandis S. Watson

American Mannagrass, American Manna Grass, Tall Manna Grass, Reed Meadowgrass

Poaceae (Grass Family)



USDA Native Status: L48 (N), AK (N), CAN (N), SPM (N)

American manna grass is a perennial grass which spreads by both thick rhizomes and stolons. Thick, stout, culms are 2-6 ft. tall and sometimes decumbent at the base. The large, showy, openly branched, purplish panicle is up to 16 in. long and nods at the summit.

Cool-season grass has broad, pale leaves and very loose, open flowering stalks. Important member of wetland communities. (Ontario Native Plants 2002)


From the Image Gallery

1 photo(s) available in the Image Gallery

Plant Characteristics

Duration: Perennial
Habit: Grass/Grass-like
Root Type: Fibrous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Leaf Venation: Parallel
Fruit Type: Caryopsis
Size Notes: Up to about 6 feet tall.

Bloom Information

Bloom Color: Purple
Bloom Time: May , Jun , Jul , Aug


USA: AK , AZ , CA , CO , CT , IA , ID , IL , IN , MA , MD , ME , MI , MN , MS , MT , ND , NE , NH , NJ , NM , NV , NY , OH , OR , PA , RI , SD , TN , UT , VA , VT , WA , WI , WV , WY
Canada: NB , NL , NS , ON , PE , QC
Native Distribution: Canada, s. to VA, TN mts., n. IL, NE, NM, AZ & CA
Native Habitat: Stream banks; non-tidal marshes; lake margins

Growing Conditions

Light Requirement: Sun
Soil Moisture: Wet
Soil Description: Wet soils.
Conditions Comments: A rapidly growing grass.


Commercially Avail: yes

Find Seed or Plants

Find seed sources for this species at the Native Seed Network.

National Wetland Indicator Status

This information is derived from the U.S. Army Corps of Engineers National Wetland Plant List, Version 3.1 (Lichvar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phytoneuron 2013-49: 1-241). Click here for map of regions.

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is on display at the following locations:

North American Native Plant Society - Etobicoke, ON
Native Seed Network - Corvallis, OR


Bibref 841 - Native Alternatives to Invasive Plants (2006) Burrell, C. C.

Search More Titles in Bibliography

Web Reference

Webref 38 - Flora of North America (2019) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.

Additional resources

USDA: Find Glyceria grandis in USDA Plants
FNA: Find Glyceria grandis in the Flora of North America (if available)
Google: Search Google for Glyceria grandis


Record Modified: 2023-01-25
Research By: TWC Staff

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