- Conium maculatum, Poison-Hemlock is a biennial herbaceous plant in the carrot family (Apiaceae) that grows 3-8 ft. (0.9-2.4 m) tall. Stems are stout, hollow, ridged, and purple-spotted. C. maculatum has a thick, white taproot that may easily be mistaken for wild parsnips. All plant parts are poisonous; however, the seeds contain the highest concentration of poison. C. maculatum is native to Africa, temperate and tropical Asia and Europe.
- Leaves are shiny green, 3-4 times pinnately compound, and clasp the stem at the swollen nodes. Crushed foliage and roots have a disagreeable, parsnip-like odor.
- Flowers are small, white, and held in umbels about 3 in. (7.6 cm) across (appearing in early summer).
- C. maculatum reproduces from seed. Fruits are ridged and flattened, and each fruit holds two seeds.
- Ecological Threat
- C. maculatum contains highly poisonous alkaloids toxic to mammals. Human deaths have occurred from harvesting and consuming the roots as wild carrots or parsnips. C. maculatum quickly colonizes disturbed habitats such as roadsides, old fields, fencerows and ditches. In natural areas it can displace native plant species and prefers riparian habitats. Many U.S states have listed C. maculatum as a noxious weed.
EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org
Invasive Listing Sources
- California Invasive Plant Council
- Colorado Noxious Weeds
- Faith Campbell, 1998
- Great Lakes Early Detection Network
- Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
- Idaho Noxious Weeds
- Illinois Invasive Plant List
- Iowa Noxious Weeds
- Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
- John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
- Kentucky Exotic Pest Plant Council - Severe Threat
- Mid-Atlantic Exotic Pest Plant Council, 2005
- Nevada Noxious Weeds
- New Mexico Noxious Weeds
- Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
- Ohio Noxious Weeds
- Oregon Noxious Weeds
- Pacific Northwest Exotic Pest Plant Council, 1998
- Pennypack Ecological Restoration Trust, Pennsylvania.
- South Dakota Noxious Weeds
- Tennessee Exotic Pest Plant Council
- Utah Noxious Weeds
- Washington Noxious Weeds
- WeedUS - Database of Plants Invading Natural Areas in the United States
- West Virginia Noxious Weeds
- Wisconsin's Invasive Species Identification, Classification and Control Rule
Other System LinksPlants: COMA2
NPDN Pest: PFFALBA
NPDN Host: 36349
|Common Name Reference:|| Weed Science Society of America Common Names List|
|Scientific Name Reference:||USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|