Cow Parsnip is a native erect perennial forb growing from 3 to 8 feet high. The stout stem is ridged, hollow and usually fuzzy. Identification is by the very broad cluster (up to a foot wide) of very small white 5-parted flowers in fairly flat-topped umbels that are atop the stem that has color ranges from green to reddish green. leaves can be 2 feet wide. Some say the plant has a foul odor, others classify it as simply pungent.
Leaves: On the stem the stalk of the leaf enlarges to a clasping sheath, the leaves have soft hairs and are 3-parted with toothed or palmate leaflets, each of which has a short hairy stalk. Lower leaves can be up to 2 feet wide and always have palmate leaflets. The most upper stem leaves may be simply 3-lobed.
The inflorescence is a compound umbel, fairly flat-topped, composed on 15 to 30 stalked smaller umbellets. At the base of each umbellet are 5 to 10 narrow leafy bracts which do not persist. [An umbel has flowers with different stalk length so as to make a flat or domed flower cluster.]
Flowers: The flowers are 5-parted with the 5 white petals deeply notched so as to appear as 10 petals. Petal tips are acute to rounded and the petal margins incurved. Several of the petals are larger than the others. There are 5 stamens with white filaments and brownish-purple anthers. The stamens are placed opposite the petals and are exserted beyond the corolla throat. There is a large yellow-green ovary with a divided style.
Seed: The fruit of Cow Parsnip is an ovate flattened structure with broad wings that, when dry, separates front to back into two seeds. Squeezing the seeds produces a Parsley odor. Dry seeds are wind dispersed but do not germinate the first year. It is believed they require a cold moist period, followed by a warm moist period, followed by another cold moist period. Best to sow in the fall and let nature take care of it.
Habitat: A plant of moist areas and moist roadsides, you will find in on marsh edges, stream sides, damp open meadows. It grows from a stout taproot and associated fibrous roots. It tolerates partial shade, but not permanently wet soils. The Garden representatives are seen near the wetland at the far end of the Woodland Garden. See Eloise Butler's notes below.
Names: The genus name, Heracleum, named after Hercules, is fitting for this plant as it is truly the robust giant of the flowered plants that form umbels. The species name, maximum, also refers to large-ness. The accepted author name for the plant classification, ‘Bartram’ refers to John Bartram (1699-1777) early American botanist and explorer who traveled extensively in the colonies collecting plants. He send many plants to Europe, including many to Linnaeus who considered him the ‘greatest natural botanist is the world.' In 1765 he became “The King’s Botanist” for North America. There is an unsettled issue in the classification field as to whether the name just described should be used for the scientific name. Some references prefer it as it reflects Bartram's work which preceded that of Michaux. Other authorities differ and believe H. lanatum Michx. should be used, where the plant classification author is Andre Michaux (1746-1802), French botanist who made many exploring expeditions in the U.S. collecting and cataloging many species. The species name, lanatum, means 'woolly', referring to the plant hair. The University of Minnesota Herbarium prefers maximum.
Comparisons: You will probably not mistake this giant for any other when the combination is large palmate leaves and umbels of very small white flowers.
Above: 1st photo - The flower cluster after mid-June (of a typical year) 2nd photo - The individual flower. Note the deep notches in the five petals several of which are larger than the others. 3rd photo - The leaf forming a sheath at the base. Note the stem ridges.
Below: 1st photo - A single flower umbel of stalked flowers with some of the small bracts still present. 2nd photo - Leaf stalks of the 3-part leaf are very hairy.
Below: The leaves are 3-parted with toothed or palmate leaflets, each of which has a short stalk. Lower leaves can be up to 2 feet wide and the one shown here has leaflets with palmate divisions and coarse toothed lobes.
Below: The fruit of Cow Parsnip is a ovate flattened structure (2nd photo) that when dry separates front to back into two seeds. In a year with an early season, such as 2012, the dry seeds are already forming at the end of June.
Below: The compound flower umbel of Cow Parsnip as seen from below showing the umbrella-like umbels with their individual flower stalks.
Below: Historical Garden Photo - A grouping of Cow Parsnip in the Woodland Garden on June 15, 1953; photo from a Kodachrome by Martha Crone. Photo courtesy Martha Crone Collection, MHS
Below: The inflorescence on a plant on June 8, 2017.
Notes: Cow Parsnip is indigenous to the Garden area. Eloise Butler's records show that she obtained plants of this species in 1911 from the area of Glenwood-Inglewood Springs in Minneapolis (which is quite close to the Garden.) Another plant was obtained from the same source on May 16, 1913 and on June 21 and Oct. 16, 1914. It is listed on Martha Crone's 1951 census of plants in the Garden. The plant is found in most counties throughout Minnesota, the exceptions widely scattered. In North America it's range is extensive, being reported in all Canadian Provinces, and in all States except the SE section.
Eloise Butler wrote this about Cow Parsnip: "It seems necessary to write a work in favor of what are usually called weeds, which may be defined as plants out of place, growing where we wish something else to grow. The Cow Parsnip shows fine decorative possibilities. A rampant growth of this herb gave character to a certain roadside. Barely an hour after a photograph was taken, the plants were mown down and nothing left in their place by monotonous stubble. A plea is offered for the next season: O scytheman, spare this weed! It is harmless, and does its best to make glad the waste places. It is named for the god Hercules on account of its massive bulk. Compare it with the Castor bean occupying the central post of honor in an ornamental mound of flowers. Has it not as vigorous a growth; are not the leaves as large and finely formed and the flowers as beautiful as that of the favored imported canna?" Published in the Minneapolis Sunday Tribune July 2, 1911
Medicinal Lore: In her study of the Minnesota Chippewa, Frances Densmore lists several native uses for this plant, the most important being in the treatment of boils. The root was boiled and then applied as a drawing poultice. Dried root and flowers combined together, also made a poultice without first boiling the root. Secondarily, a decoction made from the dried root was used as a gargle for sore throat. (Ref. #5). Tilford (Ref. #39) reports that the roots are edible but are bitter with a strong taste. Mature green seeds produce a mild anesthetic action when chewed. He also warns that some people are susceptible to dermatitis after handling Cow Parsnip.
Other uses: Fernald (Ref.#6) reports that white settlers generally shunned the plant due to the disagreeable odor and taste of raw green stalks and shoots. However it was used by natives and when cooked (boiled) with two waterings it becomes an agreeable and delicious vegetable. The roots, when cooked, resemble and taste like Rutabaga.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"