When does Woollyhead Parsnip bloom?

It typically flowers from June through August, producing rounded, woolly white flower clusters atop tall stems.

What pollinators visit Woollyhead Parsnip?

Bees, butterflies, and flies are commonly seen visiting the flower heads for nectar and pollen.

What growing conditions does Woollyhead Parsnip prefer?

It grows best in consistently moist to wet soil with part sun exposure, often along seeps, streambanks, and wet mountain meadows.

How tall does Woollyhead Parsnip get?

Mature plants send up stout, hollow stems that commonly reach several feet in height, topped with dense rounded flower clusters.

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.

Woollyhead Parsnip

Name: Pollinator Patch
Author: Pollinator Patch

Sphenosciadium capitellatum

Last reviewed: August 2026

Woollyhead Parsnip is a tall herbaceous forb found in wet mountain meadows and along streambanks in the Sierra Nevada, Cascades, and Great Basin ranges, blooming June through August with dense white flower clusters.

Woollyhead Parsnip (Sphenosciadium capitellatum) — Photo: Merrie Freed / Wikimedia Commons (Public domain)

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

CA, ID, NV, OR

Pollinators

bees, butterflies, flies

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Browse plants for this ecoregion

Northwestern Forested Mountains Sierra Nevada Southern California Mountains Central Basin and Range North American Deserts

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 Woollyhead Parsnip bloom?: It typically flowers from June through August, producing rounded, woolly white flower clusters atop tall stems.
What pollinators visit Woollyhead Parsnip?: Bees, butterflies, and flies are commonly seen visiting the flower heads for nectar and pollen.
What growing conditions does Woollyhead Parsnip prefer?: It grows best in consistently moist to wet soil with part sun exposure, often along seeps, streambanks, and wet mountain meadows.
How tall does Woollyhead Parsnip get?: Mature plants send up stout, hollow stems that commonly reach several feet in height, topped with dense rounded flower clusters.
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.

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.

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