Purple loosestrife is a perennial herb native to Europe. It grows 3-7 feet tall, with a dense bushy growth of 1-50 stems. Showy magenta flowers have 5-6 petals and bloom from July to September. Purple loosestrife has a large, woody taproot with fibrous rhizomes that form a dense mat. A single plant can produce over 100,000 seeds per year. Bushy mature plants can produce over a million seeds per year.
Purple loosestrife grows in meadows, along streams and rivers, spreading quickly, choking out native wetland vegetation, and degrades wildlife habitat. Mechanical control includes cutting, pulling, digging or drowning. Cutting before flowering will prevent seed production. Pulling and digging can be effective, but can also be disruptive by creating disturbed bare spots, which are good sites for the loosestrife seeds to germinate, or root fragments that grow into new plants. Drowning the plant requires having it completely submerged for a year. Mowing and burning have not been effective.
Herbicide control in July or August is effective to control purple loosestrife. The EC-130 Guide for Weed Management in Nebraska lists several products labeled for the control of purple loosestrife. There are two biological control insects approved for use on purple loosestrife in Nebraska. For more information on using insect to control purple loosestrife, contact your local county weed superintendent.