American Sweet Flag vs Silky Lupine - TreeTime.ca

American Sweet Flag vs Silky Lupine

Acorus americanus

Lupinus sericeus

CUSTOM GROW

CUSTOM GROW

American Sweet Flag
Silky Lupine

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.

Silky Lupine is a native perennial wildflower known for its upright spikes of blue to violet flowers. Blooming from late spring into summer, the nectar-rich, showy blossoms attract a variety of pollinators, especially bees and butterflies. The plant’s fine, silky foliage provides soft texture and visual interest, enhancing landscapes throughout the growing season.

Silky Lupine is a nitrogen-fixing plant that enriches soils and supports surrounding vegetation. Its deep roots stabilize soil, and it spreads naturally by ejecting seeds from drying pods. If spread isn’t desired, new seedlings are easy to remove. While it is foraged by some wild animals, it contains alkaloids that are toxic to livestock. Silky Lupine is well-suited to pollinator gardens, naturalization plantings, erosion control, and ecological restoration projects.

American Sweet Flag Quick Facts

Silky Lupine Quick Facts

Zone: 3a
Zone: 4a
Height: 0.9 m (3 ft)
Height: 0.6 m (2.0 ft)
Spread: 0.6 m (2.0 ft)
Spread: 0.5 m (1.5 ft)
Light: partial shade, full sun
Light: any
Moisture: wet
Moisture: dry, normal
Growth rate: fast
Growth rate: medium
Life span: short
Life span: short
Growth form: upright, colony-forming
Growth form: clump-forming
Spreading: rhizomes - high
Spreading: seeds - high
Maintenance: medium


Toxicity: toxic to sheep and other livestock
Foliage: fragrant
Foliage: Silky-haired, palmately compound leaves
Flowers: yellow floral spike
Flowers: Blue to violet pea-like flowers
Bloom time: spring to summer
Bloom time: mid to late 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