SAV watershed

Background

Purple loosestrife (Lythrum salicaria) is a plant species native to Asia and Europe, which has spread throughout much of the United States and Canada. It was first introduced to North America in the 1800s for unknown reasons, although many think it was introduced as an ornamental plant or for medicinal purposes. The plant is undeniably pretty, growing four to seven feet tall and covered by prolific and attractive purple blooms. A mature plant produces 30 or more flowering stems and can produce more than 2.5 million seeds per year.

In the absence of native competitors, purple loosestrife, which is sometimes referred to as the "Purple Plague", is a fierce competitor. It can be found in most freshwater meadows, tidal and nontidal marshes, around rivers, stream banks, ponds, lakes or ditches. Purple loosestrife has been found throughout the Chesapeake Bay watershed.

The Problem

The rapid and prolific growth of purple loosestrife:

• Creates thick stands, or monocultures, that overtake wetland areas;
• Competes with native vegetation, eliminating wetland diversity;
• Causes endangered plants and animals to lose habitat;
• Chokes waterways with its dense roots and promotes the deposition of silt, disrupting the vital water filtering action of wetland areas;
• Impairs the recreational use of wetlands and rivers by restricting water access;
• Impedes water flow in drainage ditches and can require costly dredging.
  
  

The Solution

Biological control, such as introducing loosestrife-eating beetles, is being adopted in other regions. Even with the possibility of biocontrol, which the state of Maryland is exploring, eradication of the plant is unlikely. The main goals for management will be to reduce its density and harmful effects and to prevent further spread through education and outreach.

Purple loosestrife photo courtesy: U.S. Fish and Wildlife Service

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For more information, contact the Chesapeake Bay Program Office:
410 Severn Avenue, Suite 109, Annapolis, MD 21403 / Tel: (800) YOUR-BAY / Fax: (410) 267-5777.

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Last modified: 06/12/02