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

Stem

  • Up to 6 ft. tall, 4-5 sided, covered with short hairs and often branched; multiple stems arise from root crown
Photo of Purple loosestrife

Leaves

  • Mostly opposite or whorled, narrow to lance-shaped, 2-6 in. long, smooth edges (margins), lack hair (glabrous) to hairy; NO leaf stems (petioles)
Photo of Purple Loosestrife

Flower

  • Showy; clustered on stalks at the tips of branches; 5-7 pink to purple petals surrounding a yellow center; petals are less than 0.5 in. long, each have a dark midvein and appear wrinkled or crushed
Photo of Purple loosestrife

Root

  • Taproot with some spreading roots; can associate with nitrogen-fixing bacteria
Photo of purple loosestrife

Other

  • Grows best in wet areas; often found in marshes and along the edges of pond and waterways; known to occur in Storey and Washoe counties
  • Perennial; reproduces by seed and stem fragments
  • Historically used as an ornamental plant but has escaped cultivation
 

Control

  • Repeated hand-removal of individual plants including roots can be effective; DO NOT mow
  • Several biological control agents are available
  • Apply metsulfuron to actively growing plants; glyphosate or triclopyr at bloom; imazapyr from bloom until killing frost 

Learn more about the author(s)

Heidi Kratsch
Heidi Kratsch
 

Also of Interest:

 
goatsrue by river
Nevada Noxious Weed Field Guide – Goatsrue
Goatsrue 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