Lythrum salicaria (Purple Loosestrife)

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Detailed Information

Flower:

Flowers are in a spike up to 20 inches long, densely packed with purple or pinkish-purple flowers. Individual flowers are ½ to ¾ inch across, have 5 to 7 petals (6 is most common), about 10 purple-tipped stamens and a yellow center that turns darker purple with maturity. The petals have pointed or slightly rounded tips, a dark vein down the middle, and a wrinkled texture reminiscent of crumpled tissue paper. One plant has numerous spikes.

Leaves and stem:

Leaves are up to 4 inches long and 1 inch wide, toothless, gradually tapering to a pointed tip, with a rounded or heart-shaped base and no leaf stem. Attachment is opposite, or may be in whorls of 3 or 4. The main stem is square and covered in downy hair. Established plants can have dozens of shoots and take on a bushy appearance.

Notes:

Purple Loosestrife is on the prohibited noxious weed list for Minnesota. It is exceedingly aggressive and can overtake native plants very quickly. A single mature plant can produce well over a million seeds a year.

More photos

• full length of a plant, about 4 feet tall
• a bushy Purple Loosestrife plant
• flower spikes
• a colony of Purple Loosestrife at the edge of a cat-tail marsh

Photos taken at Long Lake Regional Park, New Brighton, MN August 2006 and July 2007

Comments

Have you seen this plant in Minnesota, or have any other comments about it?