Woollyhead Parsnip
Sphenosciadium capitellatum
Last reviewed: June 2026
Sphenosciadium capitellatum (Woollyhead Parsnip) is a native Oregon forb that blooms white flowers from June through August. This wetland plant attracts bees, butterflies, and flies in partial sun to shaded conditions.
Woollyhead Parsnip is toxic to dogs and cats.
Listed as toxic by the ASPCA Animal Poison Control Center (opens in new tab) (last reviewed 2026-05-21). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435and your veterinarian's emergency line.
Pollinator Patch flags toxic plants so you can choose a pet-safe native alternative for your yard.
Light
part sun
Water
medium
Size
12"–36" H × 12"–24" W
Bloom
Jun, Jul, Aug
Native to
OR
Pollinators
bees, butterflies, flies
Browse plants for this ecoregion
Woollyhead parsnip is a medium-sized native perennial with clusters of small white flowers that bloom through summer. This plant grows in a compact clump and provides consistent garden structure with its sturdy stems and attractive flower heads.
Growing Woollyhead Parsnip
Grow Woollyhead Parsnip in part sun and medium water. Mature plants reach 12 to 36 inches tall and spread 12 to 24 inches wide. Expect low maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Woollyhead Parsnip 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.
- Parsnip name creates confusion with weedy plants
- Unknown leaf retention makes winter appearance unpredictable
- Umbel flowers may appear weedy to untrained eye
Wildlife value
The umbrella-shaped flower clusters attract a diverse range of pollinators including native bees, butterflies, and beneficial flies during its long summer bloom period.
Common questions
- When does Sphenosciadium capitellatum bloom?
- Woollyhead Parsnip blooms from June through August, producing clusters of small white flowers that attract various pollinators.
- What pollinators visit Sphenosciadium capitellatum?
- Woollyhead Parsnip attracts bees, butterflies, and flies with its umbrella-shaped flower clusters during the summer months.
- Where is Sphenosciadium capitellatum native?
- Woollyhead Parsnip is native to Oregon, where it grows in wet meadows and streamside areas in mountainous regions.
- What growing conditions does Sphenosciadium capitellatum prefer?
- Woollyhead Parsnip thrives in partial sun to shaded locations with consistently moist to wet soil conditions, making it ideal for bog gardens or streamside plantings.
- Is Woollyhead Parsnip toxic to dogs?
- Yes. Woollyhead Parsnip is listed as toxic to dogs by the ASPCA Animal Poison Control Center (aspca.org). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
- Is Woollyhead Parsnip toxic to cats?
- Yes. Woollyhead Parsnip is listed as toxic to cats by the ASPCA Animal Poison Control Center (aspca.org). If your cat has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
- Is Woollyhead Parsnip HOA-friendly?
- Woollyhead Parsnip 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.
Pollinator Patch flags toxic plants like Woollyhead Parsnip and shows pet-safe natives for your ecoregion instead.
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