Thin-leaf Sunflower
Helianthus decapetalus
Last reviewed: August 2026
Thin-leaf sunflower produces pale yellow flower heads from July through September and thrives along moist woodland edges, thickets, and meadow margins in the eastern United States.
Toxicity unknown
Thin-leaf Sunflower (Helianthus decapetalus) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
Light
full sun
Water
medium
Size
24"–60" H × 12"–24" W
Bloom
Jul, Aug, Sep
Native to
AL, AR, CT, DE and 26 more states
Pollinators
bees, butterflies, beetles
Before you buy
Your city may pay you to plant this
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Thin-leaf sunflower is a native perennial that produces cheerful yellow daisy-like flowers from July through September. This clumping sunflower reaches 2-5 feet tall and spreads moderately, making it suitable for naturalized areas and pollinator gardens.
Growing Thin-leaf Sunflower
Grow Thin-leaf Sunflower in full sun and medium water. Mature plants reach 24 to 60 inches tall and spread 12 to 24 inches wide. Expect moderate maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Thin-leaf Sunflower is an HOA-friendly choice in the right placement. Maintenance level: moderate. Tidiness: 2 out of 5.
Works well in: mid zone, backyard only.
- Can look weedy when dormant in winter
- May appear too informal for formal landscapes
- Height and spread could seem uncontrolled to some HOAs
Wildlife value
Host plant for silvery checkerspot butterfly.
The bright yellow blooms attract bees, butterflies, and beetles throughout the summer and fall. Seeds provide food for birds, particularly goldfinches and other songbirds.
Common questions
- When does thin-leaf sunflower bloom?
- Helianthus decapetalus typically blooms from July through September, producing multiple pale yellow flower heads on branching stems.
- What pollinators visit thin-leaf sunflower?
- Bees, butterflies, and beetles regularly visit the flower heads for pollen and nectar, making it a useful plant in pollinator gardens.
- What growing conditions suit thin-leaf sunflower best?
- It grows well in full sun to part shade with medium moisture, and tolerates wetter or drier soil for periods, often found along stream banks, woodland edges, and thickets.
- Does thin-leaf sunflower spread readily in a garden bed?
- Yes, it spreads by rhizomes and self seeding, so it works well in naturalized borders or informal pollinator plantings where some spread is welcome.
- Is Thin-leaf Sunflower HOA-friendly?
- Thin-leaf Sunflower is generally an HOA-friendly choice in the right placement, with moderate maintenance.
These answers were drafted with an AI model from this plant's data. Verify care details with a local expert.
Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
If something looks wrong
Common plant problems, and what to check first
These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.
- It is dying right after planting
- Leaves turning yellow
- Wilting even though I watered it
- Brown crispy leaf tips
- Bugs on the plant
Ready to grow Thin-leaf Sunflower? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Planning a bed around it? Start a free plan with this plant
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