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

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
Photo of perennial sowthistle leaf
 

Flower

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

Root

  • Creeping root system
Photo of perennial sowthistle plant with root

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

Learn more about the author(s)

Heidi Kratsch
Heidi Kratsch
 

Also of Interest:

 
Photo of many green jointed goatgrass plants that look like a field
Nevada Noxious Weed Field Guide – Jointed goatgrass
Jointed goatgrass 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