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 
Peer Review Logo
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

Extension Associated Contacts

Heidi Kratsch
Heidi Kratsch
 

Also of Interest:

 
photo of perennial sowthistle patch
Nevada Noxious Weed Field Guide – Perennial sowthistle
Perennial sowthistle 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

Master Gardeners at tabling event

Master Gardeners of Nevada

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

master gardener team sitting on tractor

Master Gardeners of Washoe County

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

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

Integrated Pest Management

Integrated Pest Management (IPM) is a strategy that reduces pests to tolerable levels with lower costs for the pest manager or home gardener and minimal effect on the environment. The IPM program at University of Nevada, Reno Extension focuses on identification and public education with resources for the community including classes, Spanish language resources and a pest directory.