Gypsy Moth Suppression Program

Jeremy Lowell - Program Coordinator
Carter Rogers - Assistant Program Coordinator

Bay County Building
515 Center Avenue, Suite 503
Bay City, Michigan 48708-5941
Voice: (989) 895-4195

Purple Loosestrife


Purple loosestrife is a beautiful but aggressive invader which arrived in eastern North America in the early 1800’s. Plants were brought to North America by settlers for their flower gardens, and seeds were present in the ballast holds of European ships that used soil to weigh down the vessels for stability on the ocean. Since it was introduced, purple loosestrife has spread westward and can be found across much of Canada and the United States


Purple loosestrife is a very hardy perennial which can rapidly degrade wetlands, diminishing their value for wildlife habitat. When purple loosestrife gets a foot hold, important habitat is degraded, and native vegetation is choked out under a sea of purple flowers. Purple loosestrife also invades drier sites; concern is increasing as the plant becomes more common on agricultural land,encroaching on farmer’s crops and pasture land. Purple loosestrife is a perennial plant found rooted in a range of wet soil habitats.It can grow in a couple feet of water or on dry shore near the water line.  Plants range from two to six feet tall, and a mature plant can develop into a large clump of stems up to five feet in diameter. The root system consists of a very thick and hard tap root, and spreading lateral roots. Seedlings that germinate in the spring grow rapidly and produce a floral spike the first year.The seeds, which are very light, are mainly dispersed by wind, water, and mud.  Purple loosestrife stem fragments are able to develop roots under favorable conditions.



Purple loosestrife’s magenta flowers occur in long spikes at the end of the stems.Along the stem, one to two flowers attach closely to the stem above each pairof leaves or bracts. Each flower has four to six, occasionally seven, petals.The petals occur above a cylindrical tube. The fruit is a capsule with many tiny seeds inside. Each mature plant canproduce up to 2.7 million seeds annually.

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