American Sweet Flag vs Fireweed - TreeTime.ca

American Sweet Flag vs Fireweed

Acorus americanus

Chamaenerion angustifolium (Epilobium angustifolium)

CUSTOM GROW

CUSTOM GROW

American Sweet Flag
Fireweed

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.

Fireweed is a native perennial wildflower known for its tall spikes of bright pink to purple blooms. Its long-lasting summer flowers are an important nectar source for pollinators such as bees, butterflies, and hummingbirds, while its seeds provide food for birds. Its showy, long-lasting display makes it visually striking in naturalized plantings.

Fireweed gets its namesake because it is often one of the first species to return after wildfires, supporting ecosystem recovery. Its wind-dispersed seeds allow it to spread readily, making it highly effective in large-scale restoration, revegetation, and naturalization projects.
Fireweed is the Provincial Flower of the Yukon.

American Sweet Flag Quick Facts

Fireweed Quick Facts

Zone: 3a
Zone: 1a
Height: 0.9 m (3 ft)
Height: 1.2 m (4 ft)
Spread: 0.6 m (2.0 ft)
Spread: 0.6 m (2.0 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: upright, dense, colony-forming
Spreading: rhizomes - high
Spreading: seeds - high, rhizomes - high
Maintenance: medium


Foliage: fragrant
Flowers: yellow floral spike
Flowers: pink-purple spikes
Bloom time: spring to summer
Bloom time: mid summer to fall
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: fire weed, great willowherb, rosebay willowherb, willow herb