Rosebay Willowherb
Chamerion angustifolium
Last reviewed: July 2026
Chamerion angustifolium (Rosebay Willowherb) is a native Rhode Island perennial that produces tall spikes of pink flowers from June through September, attracting bees, butterflies, and moths.
The USDA PLANTS Database (opens in new tab) does not flag Rosebay Willowherb as toxic to livestock.
Light
part shade
Water
medium
Size
24"–72" H × 12"–36" W
Bloom
Jun, Jul, Aug, Sep
Native to
AL, AR, CA, CO and 22 more states
Pollinators
bees, butterflies, moths
Browse plants for this ecoregion
Rosebay willowherb is a tall perennial wildflower that produces spikes of bright pink-purple flowers from summer into early fall. This native plant can reach up to 6 feet tall and spreads readily through underground rhizomes and wind-dispersed seeds. It thrives in partial shade with moderate moisture and dies back completely in winter.
Growing Rosebay Willowherb
Grow Rosebay Willowherb in part shade and medium water. Mature plants reach 24 to 72 inches tall and spread 12 to 36 inches wide. Expect low maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Rosebay Willowherb takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Can spread aggressively and look wild or weedy
- Tall growth habit may appear uncontrolled
- Dies back completely in winter leaving bare stems
Wildlife value
The long blooming period provides nectar for bees, butterflies, and moths throughout the summer and fall. Seeds are an important food source for birds, and the plant serves as a host for several moth species.
Common questions
- When does Rosebay Willowherb bloom?
- Chamerion angustifolium blooms from June through September, producing distinctive tall spikes of pink flowers.
- What pollinators visit Rosebay Willowherb?
- This native plant attracts bees, butterflies, and moths with its nectar-rich flowers during the summer blooming period.
- What growing conditions does Chamerion angustifolium prefer?
- Rosebay Willowherb tolerates full sun to partial shade and prefers medium to high moisture conditions. It often colonizes disturbed areas and forest clearings.
- Is Rosebay Willowherb toxic to livestock?
- The USDA PLANTS Database does not flag Rosebay Willowherb as toxic to livestock.
- Is Rosebay Willowherb HOA-friendly?
- Rosebay Willowherb takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Ready to grow Rosebay Willowherb? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
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