American Sweet Flag vs Sweetgrass - TreeTime.ca

American Sweet Flag vs Sweetgrass

Acorus americanus

Anthoxanthum nitens (Hierochloe odorata)

CUSTOM GROW

CUSTOM GROW

American Sweet Flag
Sweetgrass

American Sweet Flag is a native perennial wetland plant found along shorelines, streams, wet meadows, and marshes. Its extensive rhizome system allows it to spread and stabilise soil, helping maintain the edges of ponds and streams. This dense growth provides cover for small animals and supports overall wetland biodiversity, while the rhizomes and seeds serve as food for small mammals and waterfowl. Cold-hardy and resilient, it is well-suited for ecological restoration, riparian plantings, erosion control, and naturalization projects.

The plant grows in dense clumps with tall, sword-shaped leaves that release a citrus-like scent when bruised. The rhizomes are aromatic, with a spicy, cinnamon-like fragrance that has been used in perfumery and flavouring. In early summer, American Sweet Flag produces a distinctive floral spike (spadix), adding visual interest to wetland plantings.

Sweetgrass is a cool-season perennial grass best known for its sweet, vanilla-like fragrance. The scent comes from coumarin in the leaves, which is pleasant to humans but has a bitter taste that makes the plant less appealing to deer and other herbivores. As a cool-season grass, Sweetgrass grows most vigorously in spring and fall, slowing or even going dormant during the heat of summer.

It spreads quickly through creeping rhizomes and can be difficult to remove once established, so it is best planted in areas where its spread will not cause problems. Due to its deep, vigorous root system and preference for moist soils, Sweetgrass is especially useful for erosion control, soil stabilization, riparian plantings, and naturalization projects.

Note: Sweetgrass was formerly classified under the scientific name Hierochloe odorata and its subspecies. The subspecies found in Canada are currently considered two distinct species: Anthoxanthum hirtum, which is native across Canada, and Anthoxanthum nitens, which is native to Eastern Canada. Because these two species are alike and share many overlapping common names, they are often considered as only one species.

American Sweet Flag Quick Facts

Sweetgrass Quick Facts

Zone: 3a
Zone: 1a
Height: 0.9 m (3 ft)
Height: 0.5 m (1.5 ft)
Spread: 0.6 m (2.0 ft)
Spread: 0.5 m (1.5 ft)
Light: partial shade, full sun
Light: partial shade, full sun
Moisture: wet
Moisture: normal, wet
Growth rate: fast
Growth rate: fast
Life span: short
Life span: short
Growth form: upright, colony-forming
Growth form: arching to upright, colony-forming
Spreading: rhizomes - high
Spreading: rhizomes - high, seeds - low


Toxicity: toxic if large amounts ingested
Foliage: fragrant
Foliage: fragrant, bright green
Flowers: yellow floral spike
Bloom time: spring to summer
Hybrid: no
Hybrid: no
Catkins: no
Catkins: no


Native to: AB, BC, SK, MB, ON, QC, NS, NB, NL, NT, PE
Native to: AB, BC, SK, MB, ON, QC, NS, NB, NL, YT, NT, NU, PE
Other Names: american sweetflag
Other Names: bison grass, buffalo grass, holy grass, sweet grass, vanilla sweetgrass