Stem

Up to 6 ft. tall, semi-woody, waxy and lacks hair (glabrous); many stems can arise from each crown; often branched near top; branches arise from leaf axils

Photo of perennial sowthistle patch with yellow flowers

Leaves

Alternate; upper leaves are smaller and fewer than lower leaves; leaf bases clasp the stem; exude white, milky sap when broken
Edges (margins) smooth to deeply lobed and spiny

Flower

Yellow; less than 2 in. wide; base of flower is vase shaped; flower base and stalk usually covered with stiff, sticky hairs

Root

Creeping root system

Other

Grows best in moist, fertile soils; often infests crop fields, gardens, waste areas and ditch banks; known to occur in Washoe and White Pine counties
Perennial; reproduces by seed and roots; seed is wind-dispersed

Control

Tilling and mowing not effective; pulling can be effective, but the entire root must be removed. Preventing seed production is essential for control
Apply 2,4-D, aminopyralid, clopyralid, MCPA, or picloram to actively growing plants before bud stage

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

Extension Associated Contacts

Heidi Kratsch

Also of Interest:


Needs Assessment for Noxious Weeds in Churchill County: Part 4 of 5 - Criteria for Herbicide Use and Selection This fact sheet is the fourth in a series of five that reports the results of a needs assessment survey completed by faculty in University of Nevada Cooperative Extension (UNCE). The survey attempted to identify the major issues related to the management and control of weeds in N... Davison, J., Powell, P., Schultz, B., and Singletary, L. 2012, University of Nevada Cooperative Extension
Nevada’s Priority Agricultural Weeds: Hoary Cress Plants commonly referred to as hoary cress (Cardaria sp.), or short whitetop, are one of three different but closely related perennial forbs. The Cardaria species are widespread across all eleven Western states, including every county in Nevada. B. Schultz, S. Foster 2021, Extension, University of Nevada, Reno, SP-21-03
Nevada Noxious Weed Field Guide – African mustard African mustard is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed. Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., H. Kratsch, Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
Nevada Noxious Weed Field Guide – Common St. Johnswort Common St. Johnswort is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed. Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
Nevada Noxious Weed Field Guide – Crimson fountaingrass Crimson fountaingrass is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed. Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide

Associated Programs

Garden plant and pest sprayers image by Olga Seifutdinova from Getty Images

Integrated Pest Management

Integrated Pest Management program is a long-term management strategy that uses a combination of tactics to reduce pests to tolerable levels with potentially lower costs for the pest manager and minimal effect on the environment.

Master Gardeners of Washoe County

Master Gardeners provide free, research-based horticulture information to Nevadans.

Master Gardeners of Nevada

Program trains local gardeners to provide research-based horticulture information to Nevadans

Nevada Noxious Weed Field Guide – Perennial sowthistle