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

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)

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

Root

Taproot with some spreading roots; can associate with nitrogen-fixing bacteria

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

Also of Interest:

Nevada Noxious Weed Field Guide – Purple loosestrife