Heracleum lanatum (Common Cow Parsnip)

Plant Info
Also known as: American Cow-parsnip
Genus:Heracleum
Family:Apiaceae (Carrot)
Life cycle:perennial
Origin:native
Habitat:part shade, sun; moist fields, thickets, streambanks
Bloom season:May - July
Plant height:4 to 10 feet
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: 5-petals Cluster type: flat

[photo of flowers] Flowers are in flat clusters (umbels) 4 to 8 inches across, each cluster made up of 15 to 30 groups (umbellets) of white flowers. Individual flowers are about ¼ inch across with 5 white petals notched at the tip. The flowers on the outer edge are larger and have more deeply divided petals of unequal size. There are 5 white tipped stamens surrounding the creamy button center. One plant normally has a few to several clusters.

Leaves and stem: Leaf attachment: alternate Leaf type: palmate

[photo of leaves] Leaves are palmately compound in 3's, softly hairy, with fine sharp teeth around the edges, to 18 inches long and wide near the base of the plant, becoming smaller as they ascend the stem. The end leaflet is largest and lobed in 3 parts; each lobe may be further divided. Attachment is alternate.

[photo of stem] The leaf stem is long and sheathed where it clasps the main stem. The main stem is thick and hollow, covered in short fine hairs.

Fruit:

[photo of fruit] Fruit is a flattened oval to heart-shaped pod about 1/3 inch long with parallel lines. It turns from green to brown as the seed matures.

Notes:

Cow Parsnip is present throughout Minnesota, often seen in late spring and early summer along roadsides in wet ditches. It has broader flower clusters than most other members of the carrot family; that and the large leaves make it easy to ID. Cow Parsnip is the native counterpart to the highly invasive non-native Giant Hogweed (Heracleum mantegazzianum), which is not yet present in Minnesota but is making its way here.

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More photos

Photos by K. Chayka taken at Wild River State Park, Chisago County. Photo courtesy Peter M. Dziuk taken in Yellow Medicine County.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Barb in southwest MN
on: 2010-08-04 20:22:13

We have seen these growing in many nearby parks and recreational areas. I always warn my children and grandchildren to stay away from them because they so closely resemble their very poisonous relatives. Besides, contact can make skin sensitive to the sun and cause irritation.

Posted by: Anne in North Shore, specifically Sugar Loaf Cove
on: 2014-04-24 19:12:09

or could it be giant hog weed?

Posted by: K. Chayka
on: 2014-05-31 17:49:04

As far as we know, giant hogweed is not confirmed in MN. Cow parsnip is common, though

Posted by: Mae in near Lake of the Woods
on: 2014-06-23 16:02:05

I've seen several of these plants, at least I think they are cow parsnips. I thought at first they might be giant hogweed

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