: Giant cow parsley
: This species has been listed as a noxious weed under federal law and is also prohibited under Michigan law.
: Extremely tall (2.5-6 m, 8-20 ft) biennial or short-lived perennial with a deep (40-65 cm, 16-26 in) tap root.
: Alternate, large- up to 1.5 m (5 ft) wide; deeply divided and dissected leaves; hairy beneath; leaf stalk enlarged and surrounding the stem; upper leaves gradually becoming smaller.
: Thick; 5-10 cm (2-4 in) in diameter; hollow; purple-mottled; with coarse white hairs.
: Small, white in color, clustered into large, slightly curved umbels at the top of each stem, typically bloom once and then die (robust biennial or monocarpic perennial); blooms June through July.
Fruit and seeds
: Seeds in flat, dry, oval pods; 8-15 mm in length; one plant can produce up to 100,000 seeds.
: Native to Asia, now prefers open, moderately moist, cool sites but can be found in a range of habitats.
: By seed or by re-sprouts from cut stumps.
: Cow parsnip (Heracleum maximum
) is smaller (up to 8 ft tall), has dense fine white hairs under leaves and lacks purple mottling on stem; Angelica has smooth, sometimes purplish stems but lacks mottling and hairs.
Monitoring and rapid response
: Monitor riparian sites and disturbed edge habitat in partial shade. Sap causes increased photosensitivity; may cause severe burns, blistering, dermatitis and dark scars, and even blindness; protect skin; mowing stimulates budding from the rootstalk; plants may be dug out, remove entire root, Research herbicide options as not all are effective. As this species has a limited distribution in Michigan, it is important to document new occurrences. Please obtain flowering or fruiting specimens and submit to: Anton Reznicek, Curator (Vascular Plants), University of Michigan Herbarium, 3600 Varsity Drive, Ann Arbor, MI 48108-2287.
: The Michigan Natural Features Inventory
(MNFI) has partnered with MISIN to provide the information in this fact sheet. Species images and/or information were used with permission from "A Field Identification Guide to Invasive Plants in Michigan's Natural Communities
" and "A Field Guide to Invasive Plants of Aquatic and Wetland Habitats for Michigan