Swamp Sunflower
Helianthus angustifolius
Last reviewed: June 2026
Swamp Sunflower is a native wildflower found across the eastern and central United States that produces bright yellow blooms from September through November in wet soils and full sun.
Swamp Sunflower (Helianthus angustifolius) is not on the ASPCA Animal Poison Control Center toxic plant list for dogs or cats (aspca.org (opens in new tab), last reviewed 2026-05-21). If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
The USDA PLANTS Database (opens in new tab) does not flag Swamp Sunflower as toxic to livestock.
Light
full sun
Water
high
Size
36"–72" H × 6"–12" W
Bloom
Sep, Oct, Nov
Native to
AL, AR, FL, GA and 18 more states
Pollinators
butterflies
Browse plants for this ecoregion
Swamp Sunflower is a tall, narrow perennial that produces bright yellow daisy-like flowers from September through November. This native Texas wildflower thrives in moist conditions and can reach up to 6 feet tall with a relatively compact spread. The late-season blooms provide important color when many other plants are finishing for the year.
Growing Swamp Sunflower
Grow Swamp Sunflower in full sun and high water. Mature plants reach 36 to 72 inches tall and spread 6 to 12 inches wide. Expect low maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Swamp Sunflower 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.
- Height exceeds typical HOA-friendly range
Wildlife value
The abundant fall flowers are excellent nectar sources for migrating butterflies and other pollinators during a critical time when few other plants are blooming. Seeds also provide food for birds in winter.
Common questions
- When does Swamp Sunflower bloom?
- Swamp Sunflower blooms in fall, typically from September through November, providing late-season color when many other wildflowers have finished.
- What growing conditions does Helianthus angustifolius prefer?
- This native sunflower thrives in consistently moist to wet soils and full sun conditions, making it ideal for rain gardens, pond edges, and naturally wet areas.
- What wildlife does Swamp Sunflower support?
- Swamp Sunflower attracts butterflies with its nectar-rich fall blooms and provides seeds for birds later in the season.
- Where is Swamp Sunflower native?
- Helianthus angustifolius is native to much of the eastern and central United States, from New York south to Florida and west to Texas, Iowa, and Oklahoma.
- Is Swamp Sunflower toxic to dogs?
- Swamp Sunflower is not on the ASPCA Animal Poison Control Center toxic plant list for dogs (aspca.org).
- Is Swamp Sunflower toxic to cats?
- Swamp Sunflower is not on the ASPCA Animal Poison Control Center toxic plant list for cats (aspca.org).
- Is Swamp Sunflower toxic to livestock?
- The USDA PLANTS Database does not flag Swamp Sunflower as toxic to livestock.
- Is Swamp Sunflower HOA-friendly?
- Swamp Sunflower 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.
Does Swamp Sunflower fit your yard? Open it in Pollinator Patch to check it against your sun, soil, and HOA-conscious filters.