Purple Loosestrife (Lythrum salicaria)
Loosestrife family
EDRR Early Detection Rapid Response: If found, report immediately! Contact the Juneau Invasive Weed Coordinator at (907) 586-6878.
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Plant Identification: A perennial plant which grows 2 to 8 feet tall. Produces tall spikes of purple-magenta flowers, each with 5 to 7 “ruffled”petals and a small yellow center. Lance-shaped leaves have smooth edges, and are usually arranged opposite one another, in groups of 2 or 3 along the stem. As many as 40 stems arise from the base of a well-established mature plant. Stems are 4 or 5-sided in cross-section. Purple-pink flower spikes may be confused with Alaska’s native fireweed (Epilobium spp.) but in Alaska purple loosestrife blooms in the fall, well after fireweed blooms have faded.
Threat: An aggressive wetland invader, purple loosestrife chokes waterways, degrading wildlife habitat and fish spawning areas. Single plants can produce millions of tiny seeds.
Found: Not known to occur in Juneau beyond a few ornamental gardens. Look for purple loosestrife in wetlands.
Distribution Map:Purple Loosestrife (Lythrum salicaria) (External Link to EDDMapS website)
Detailed information sheet ( Link to .pdf at UAA ENRI Alaska Natural Heritage Program)