Stem

Up to 5 ft. tall, stout, lacks hair (glabrous) and hollow except at nodes; usually with purple streaks; often branched

Leaves

Pinnate-compound; leaflets are lance-shaped, 1-4 in. long and lack hair; edges (margins) are toothed

Flower

Small, white and arranged in umbrella-like clusters at end of a stalk

Root

Swollen taproot at stem base that can be cut open to reveal multiple narrow, hollow, horizontal chambers; fluid released from cut stem bases is orange-yellow or brown, has the odor of parsnip and is highly toxic

Other

Grows best in moist soils; often found in crop fields, roadsides, waste areas and along waterways; known to occur in Douglas and Lyon counties; native to North America
Perennial; reproduces by seed
Highly toxic to animals and humans, even in small quantities

Control

Repeated cultivation or hand-removal can be effective; avoid contact with skin
Apply 2,4-D, glyphosate, or MCPA to actively growing plants

Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Nevada Noxious Weed Field Guide – Waterhemlock, Extension, University of Nevada, Reno, Field Guide

Extension Associated Contacts

Heidi Kratsch

Also of Interest:


A Northern Nevada Homeowner's Guide to Identifying and Managing: Carpenter Ants Carpenter ants are some of the largest ants found in the United States. They are capable of damaging compromised wood in buildings and are there for important to identify and monitor quickly. Andrews, M., Hanson Mazet, W., and Kratsch, H. 2023, Extension, University of Nevada, Reno, FS-23-30
A Northern Nevada Homeowner's Guide to Identifying and Managing: Harvester Ants Harvester ants have large ant hill that are capable of reaching 12 feet in diameter and 3 feet deep. Harvester ants only become aggressive when disturbed and are capable of stinking. They do no invade homes, but are pests of lawns and gardens. Andrews, M., Hanson Mazet, W., and Kratsch, H. 2023, Extension, University of Nevada, Reno, FS-23-32
"A Northern Nevada Homeowner's Guide to Identifying and Managing: House Ants House ants are some of the most common ants found in our communities, learn about identification of the two different species as well as control tactics. Andrews, M., Hanson Mazet, W., and Kratsch, H. 2024, Extension, University of Nevada, Reno, FS-24-14

Nevada Noxious Weed Field Guide – Waterhemlock