Purple Loosestrife

Lythrum salicaria

Purple loosestrife is a non-native, invasive wetland plant that has:

• Spikes of bright purple to magenta flowers, which are produced from July to September.
• Square, six-sided stems.
• Lance- or linear-shaped leaves that grow up to 4 inches long and are arranged in opposite pairs or whorls of three. In fall, leaves often turn red for about two weeks before fading and falling from the stems.

Purple loosestrife can grow to about 6.5 feet tall.

Where does purple loosestrife grow?

Colonies of purple loosestrife grow mostly in disturbed fresh and brackish wetlands, as well as other moist or marshy sites, including:

• Natural wetlands
• Bogs
• Swamps
• Ditches
• Roadsides
• Wet meadows
• Edges of ponds, rivers and reservoirs

How does purple loosestrife reproduce?

Purple loosestrife spreads as its seeds disperse. An individual purple loosestrife plant can yield more than 2 million seeds per year. The tiny, reddish-brown seeds spread mainly by wind, rain and water, as well as on the feet of waterfowl and wetland animals. Seedlings germinate in the spring or summer.

Purple loosestrife also spreads through roots and stem fragments. The plant's thick, fleshy roots can produce numerous shoots. New plants can also grow from the fragments of roots and stems that are cut or mowed down.

Other facts about purple loosestrife:

• Purple loosestrife grows rapidly, out-competing and displacing native wetland species like cattails and bulrushes.