American Sweet Flag vs Sulphur-Flower Buckwheat - TreeTime.ca

American Sweet Flag vs Sulphur-Flower Buckwheat

Acorus americanus

Eriogonum umbellatum

CUSTOM GROW

CUSTOM GROW

American Sweet Flag
Sulphur-Flower Buckwheat

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.

Sulphur-Flower Buckwheat is a native perennial wildflower known for its dense clusters of cream to yellow flowers. The long-lasting blooms persist from late spring into summer, providing an extended nectar source for a variety of pollinators. The flower buds are often red-tinted before opening. As the blooms age, they shift to orange or red, adding seasonal interest and making them well-suited to dried flower arrangements. Its seeds are also eaten by birds, adding to its ecological value.

Depending on climate and conditions, Sulphur-Flower Buckwheat may be evergreen to semi-evergreen, or its foliage may turn red during fall. Its deep roots and spreading growth stabilize rocky or sandy soils, making it useful for erosion control. Exceptionally hardy once established, it requires little care and thrives in challenging environments, making it an excellent choice for pollinator gardens, naturalization, and ecological restoration projects.

American Sweet Flag Quick Facts

Sulphur-Flower Buckwheat Quick Facts

Zone: 3a
Zone: 3a
Height: 0.9 m (3 ft)
Height: 0.2 m (0.5 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: dry, normal
Growth rate: fast
Growth rate: medium
Life span: short
Life span: short
Growth form: upright, colony-forming
Growth form: upright to spreading, clump-forming
Spreading: rhizomes - high
Spreading: seeds - low


Foliage: fragrant
Foliage: leathery
Fall colour: reddish bronze
Flowers: yellow floral spike
Flowers: colour varies, typically white to yellow
Bloom time: spring to summer
Bloom time: mid spring to mid 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
Other Names: american sweetflag
Other Names: sulphur buckwheat, sulphur flower, wild buckwheat