North America Native Plant

American Mannagrass

Botanical name: Glyceria grandis var. grandis

USDA symbol: GLGRG

Life cycle: perennial

Habit: grass

Native status: Native to Alaska âš˜ Native to Canada âš˜ Native to the lower 48 states âš˜ Native to St. Pierre and Miquelon  

Synonyms: Glyceria maxima (Hartm.) Holmb. var. americana (Torr.) B. Boivin (GLMAA)  âš˜  Glyceria maxima (Hartm.) Holmb. ssp. grandis (S. Watson) Hultén (GLMAG)  âš˜  Panicularia grandis (S. Watson) Nash (PAGR4)   

American Mannagrass: A Graceful Native Grass for Wet Gardens If you’re looking to add some natural elegance to those soggy spots in your yard, American mannagrass (Glyceria grandis var. grandis) might just be the perfect solution. This tall, graceful perennial grass is like nature’s own water-loving fountain, creating beautiful arching ...

Rare plant alert!

Region: New Jersey

Status: Endangered, Listed Pinelands, Highlands Listed, S2: New Jersey Highlands region ⚘ New Jersey Pinelands region ⚘ Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

American Mannagrass: A Graceful Native Grass for Wet Gardens

If you’re looking to add some natural elegance to those soggy spots in your yard, American mannagrass (Glyceria grandis var. grandis) might just be the perfect solution. This tall, graceful perennial grass is like nature’s own water-loving fountain, creating beautiful arching displays while helping solve those tricky wet-soil challenges that leave many gardeners scratching their heads.

What Makes American Mannagrass Special?

American mannagrass is a true native treasure, naturally occurring across an impressive range from Alaska all the way down through Canada and most of the lower 48 states. This widespread distribution tells us something important: this grass knows how to adapt and thrive in diverse conditions, making it a reliable choice for gardeners across much of North America.

As a member of the grass family, American mannagrass grows as what botanists call a graminoid – basically a fancy way of saying it’s got that classic grass-like appearance we all recognize. But don’t let its familiar form fool you; this perennial packs some serious landscaping punch.

Where American Mannagrass Calls Home

This adaptable native can be found growing naturally across an extensive range including Alberta, British Columbia, Alaska, Manitoba, New Brunswick, Arizona, California, Nova Scotia, Ontario, Colorado, Prince Edward Island, Connecticut, Quebec, Delaware, Saskatchewan, Yukon, Northwest Territories, Idaho, Illinois, Indiana, Iowa, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oregon, Pennsylvania, Rhode Island, South Dakota, Tennessee, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming, and Newfoundland.

A Word of Caution: Rarity Matters

Here’s something important to know: while American mannagrass thrives across much of North America, it’s actually listed as endangered in New Jersey, where it holds a rarity status of S2 and is protected in both the Pinelands and Highlands regions. This means if you’re considering adding this beauty to your garden, it’s crucial to source your plants responsibly from reputable native plant nurseries rather than collecting from wild populations.

Why Your Garden (and Local Wildlife) Will Love It

American mannagrass isn’t just a pretty face – it’s a hardworking member of the garden community. This perennial grass excels at:

  • Providing erosion control along water features
  • Creating habitat structure for beneficial insects
  • Adding vertical interest and movement to wet areas
  • Offering golden fall color for extended seasonal appeal
  • Supporting wetland restoration efforts

The tall, arching seed heads create a graceful fountain-like effect that dances beautifully in the breeze, while the foliage provides excellent backdrop for other wetland plants.

Perfect Garden Situations

American mannagrass shines brightest in:

  • Rain gardens and bioswales
  • Pond and stream margins
  • Wet meadow gardens
  • Naturalized landscapes
  • Areas prone to seasonal flooding

If you’ve got a spot that stays consistently moist or even floods occasionally, this grass will thank you for it.

Growing American Mannagrass Successfully

The good news is that American mannagrass is relatively low-maintenance once you understand its basic needs. This hardy perennial thrives in USDA hardiness zones 3-8, making it suitable for most northern and temperate climates.

Light Requirements: Full sun to partial shade (though it performs best with at least 6 hours of direct sunlight)

Soil Needs: Wet to consistently moist soils are essential. This grass actually tolerates flooding, making it perfect for those problem areas where other plants struggle.

Planting Tips: Spring is the ideal time to plant American mannagrass. Space plants adequately to allow for their mature spread, and ensure they have access to consistent moisture from day one.

Care Requirements: Once established, this grass is remarkably self-sufficient. The main requirement is maintaining adequate soil moisture – think of it as nature’s way of keeping things simple!

The Bottom Line

American mannagrass offers gardeners a chance to work with nature rather than against it. If you have wet areas that challenge other plants, this elegant native grass provides both practical solutions and aesthetic appeal. Just remember to source your plants responsibly, especially given its endangered status in some regions. When grown thoughtfully, American mannagrass can transform problematic wet spots into graceful, wildlife-friendly features that celebrate our native plant heritage.

Whether you’re creating a rain garden, restoring a wetland area, or simply trying to make the most of that soggy corner of your yard, American mannagrass deserves serious consideration. It’s proof that sometimes the best solutions are the ones that have been growing right under our noses all along.

American Mannagrass

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Commelinidae

Order

Cyperales

Family

Poaceae Barnhart - Grass family

Genus

Glyceria R. Br. - mannagrass

Species

Glyceria grandis S. Watson - American mannagrass

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA