Stem
- Up to 10 ft. tall, green with purple spots, stout, hollow except at nodes and highly branched with lengthwise ridges
Leaves
- Triangular, 4-12 in. long, finely pinnate-divided (fern-like) and lack hair (glabrous); leaflets have toothed edges; foliage has a musty odor
Flower
- Small and white; arranged in umbrella-like clusters at end of a stalk
Other
- Grows best in moist sites; often infests crop fields, waterways, roadsides and waste areas; known to occur in Carson City, Douglas, Elko, Lander, Lincoln, Lyon, Nye, Storey, Washoe, and White Pine counties
- Biennial; reproduces by seed
- Highly toxic to animals and humans when consumed
Control
- Repeated mowing or tillage prior to seed production is effective; hand-removal by cutting the taproot below the crown can also eliminate plants, avoid contact with skin
- An insect biological control agent is available
- Apply 2,4-D, chlorsulfuron, glyphosate, metsulfuron or triclopyr to actively growing young plants; aminopyralid, imazapic, or imazapyr preemergence or on young plants
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B.
2020,
Nevada Noxious Weed Field Guide – Poison-hemlock,
Extension, University of Nevada, Reno, Field Guide
