Skip to main content

American Cow-parsnip

Heracleum lanatum

Last reviewed: August 2026

American Cow-parsnip (Heracleum lanatum)
Photo: Dcrjsr / Wikimedia Commons (CC BY 3.0)

Toxicity unknown

American Cow-parsnip (Heracleum lanatum) 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

part sun

Water

medium

Size

36"–96" H × 24"–48" W

Bloom

Jun, Jul, Aug

Native to

AL, AZ, CA, CO and 40 more states

Pollinators

bees, beetles, flies

Before you buy

Your city may pay you to plant this

Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 445 programs across 44 states, each with a link to the provider and the date we last checked it.

Find rebates in your area

Browse plants for this ecoregion

Coast RangePuget LowlandMarine West Coast ForestNorthwestern Forested MountainsSierra NevadaCentral California Foothills and Coastal MountainsNorth American DesertsSouthern RockiesHigh PlainsNorthwestern Great PlainsNorthern Glaciated PlainsWestern Corn Belt PlainsGreat PlainsNorthern ForestsNorthern Lakes and ForestsNorth Central Hardwood ForestsDriftless AreaSoutheastern Wisconsin Till PlainsCentral Corn Belt PlainsNortheastern HighlandsNortheastern Coastal ZoneNorthern Allegheny PlateauErie Drift PlainNorthern PiedmontBlue RidgeRidge and ValleyCentral AppalachiansWestern Allegheny PlateauInterior River Valleys and HillsAcadian Plains and Hills

American cow-parsnip is a tall, dramatic native perennial with large umbrella-shaped white flower clusters and broad, maple-like leaves. This robust plant can reach up to 8 feet tall and creates a bold presence in partially shaded, moist areas. It blooms from June through August with impressive flower heads that can span over a foot across.

In an HOA neighborhood

American Cow-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.

  • Extremely large size appears overgrown
  • Wild, unmanicured appearance
  • Can be confused with invasive giant hogweed

Wildlife value

The large flower clusters attract numerous pollinators including native bees, beetles, and flies during its long summer bloom period. Its substantial size and extended flowering make it particularly valuable for supporting diverse pollinator populations.

Common questions

How much sun does American Cow-parsnip need?
American Cow-parsnip grows best in part sun conditions.
When does American Cow-parsnip bloom?
American Cow-parsnip blooms in June, July, and August.
Where is American Cow-parsnip native?
American Cow-parsnip (Heracleum lanatum) is native to AL, AZ, CA, CO and 40 more states, per the World Checklist of Vascular Plants (Kew).
What pollinators does American Cow-parsnip attract?
American Cow-parsnip draws bees, beetles, and flies.
Is American Cow-parsnip HOA-friendly?
American Cow-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 World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

Ready to grow American Cow-parsnip? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

Add this plant to your garden
iPhone appAndroid app

Not sure where to start? Take the 2-minute yard quiz