Plants of the Eloise Butler Wildflower Garden

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 a 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: At 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 leaflet has a short hairy stalk. Lower leaves can be up to 2 feet wide and always have 3-parted palmate leaflets. The most upper stem leaves may be simply 3-lobed, not 3-parted.

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 branching from a common point with stalk lengths about equal so as to make a flat to domed flower cluster giving all flowers equal access to sunlight.]

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 2-part 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, germinating the second year. Best to sow in the fall and let nature take care of it.

Habitat: Cow Parsnip is 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 was the most important contributor of plants to European gardens and herbariums of that era. Linnaeus considered him the ‘greatest natural botanist is the world. In 1765 he became “The King’s Botanist” for North America although King George paid little attention to what he sent. His and his son William’s writings made a deep influence on the school of Romantic writers of England.

There is an unsettled issue in the classification field as to whether the species 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. His classification did not appear until he published Flora Boreali-Americana (2 vols., 1803, (published posthumously).The species name, lanatum, means 'woolly', referring to the plant hair. The University of Minnesota Herbarium prefers maximum and Flora of North America has not yet published an updated text on the Apiaeae family.

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.