Heracleum maximum W. Bartram. Common name: Masterwort, Cow-parsnip, American Hogweed. Phenology: May-Jul; Jul-Aug. Habitat: Northern hardwood forests, roadbanks, meadows, forest openings, grassy balds, rich floodplain forests. Distribution: NL (Labrador) west to AK, south to DE, PA, OH, IN, IL, MO, KS, NM, AZ, CA, and in the Appalachians south to w. NC, e. TN, and n. GA; also in e. Siberia.
Origin/Endemic status: Native
Taxonomy Comments: The synonymy reflects two questions, one nomenclatural, the other taxonomic. North American plants are very similar to European ones, leading some workers to treat our plants as a subspecies or variety of the European. If recognized as specifically distinct from Eurasian H. sphondylium, the nomenclatural question is whether to accept Bartram's (older) name as validly published.
Synonymy ⓘ: = Can, F, FNA13, GW2, Il, K4, Mi, NE, NY, Tn, Va, WV; = Heracleum lanatum Michx. — C, G, MC, Pa, RAB, S13, Tat, W; = Heracleum sphondylium L. ssp. montanum (Schleich. ex Gaudin) Briq. — GrPl, Mo2; = Heracleum sphondylium L. var. lanatum (Michx.) Dorn. Basionym: Heracleum maximum W.Bartram 1791
Links to other floras: = Heracleum maximum - FNA13
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Wetland Indicator Status:
- Atlantic and Gulf Coastal Plain: FAC
- Eastern Mountains and Piedmont: FAC
- Great Plains: FAC
- Midwest: FACW
- Northcentral & Northeast: FACW
Heliophily ⓘ: 5
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© Keith Bradley | Original Image ⭷
© Gary P. Fleming | Original Image ⭷
© Edwin Bridges | Original Image ⭷
© Will Stuart | Original Image ⭷
© Alan Cressler: Heracleum maximum, Wolf Ridge, Cohutta Wilderness, Cherokee National Forest, Polk County, Tennessee 1 by Alan Cressler source | Original Image ⭷
© Edwin Bridges | Original Image ⭷
© Edwin Bridges | Original Image ⭷
© Edwin Bridges | Original Image ⭷
© Edwin Bridges | Original Image ⭷
© Edwin Bridges | Original Image ⭷Feedback
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Horticultural Information
Intro: Large, rank-smelling perennial of road banks, meadows and forest openings.
Stems: Stems coarse, hollow, ribbed/grooved, light green and covered with spreading, white hairs.
Leaves: Leaves alternate, large and coarse, on petioles with conspicuous purple-veined sheaths, and ternately divided (lower ones may be pinnately divided), the leaflets oval and irregularly toothed or cleft.
Inforescence:
Flowers: Flowers in a large (to 8 in. wide) terminal compound umbel as well as in smaller umbels from upper leaf axils; they are tiny, with 5 white petals.
Fruits: Fruit a hairy, 2-parted, elliptical-flattened schizocarp.
Comments: This is the largest species of the carrot family in North America.
Height: 3-10 ft.
plant sale text:
bloom table text:
description: Large, rank-smelling perennial of road banks, meadows and forest openings.
stems: Stems coarse, hollow, ribbed/grooved, light green and covered with spreading, white hairs.
leaves: Leaves alternate, large and coarse, on petioles with conspicuous purple-veined sheaths, and ternately divided (lower ones may be pinnately divided), the leaflets oval and irregularly toothed or cleft.
inflorescence:
flowers: Flowers in a large (to 8 in. wide) terminal compound umbel as well as in smaller umbels from upper leaf axils; they are tiny, with 5 white petals.
fruits: Fruit a hairy, 2-parted, elliptical-flattened schizocarp.
comments: This is the largest species of the carrot family in North America.
cultural notes:
germination code:
native range:
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