Scientific Name: Lythrum salicaria

Common Name: purple loosestrife

Other Common Names: purple lythrum, rainbow weed, salicaire, spiked loosestrife

Habit: Seedlings have ovate hairless cotyledons 3-6 mm long and 2-3 mm wide. Mature plants reach heights of 50-150 cm tall and arise from thick fleshy roots. Stems have several branches covered with soft hairs and are capable of spreading by bits of stem, root and seed.

Leaves: Leaves slightly hairy are lance shaped and can be opposite or in whorls of 3.

Identifying Characteristics: Found in moist places, purple flowers, and opposite leaves.

Flower Seed Head: Flowers appear in spikes on the end of branches and are purple with 5-7 petals, 7-10 mm long.

Seed Fruit: Fruit are 2 chambered capsules containing several seeds. A single plant can produce as many 2 million seeds a year.

Where Found: Found throughout the northeastern United States this plant can destroy wetlands taking the place of native vegetation. This species is a problem for cranberry bogs, spring flooded pastures, ditches, canals, and roadsides.

  • Life cycle: perennial

  • Milky sap: Not Present

  • Plant type: Herb

  • Thorns: Not Present

  • Plant family: Lythraceae

  • Leaf arrangement: whorled; opposite; alternate

  • Leaf shape: lance; oval; needle; heart

  • Leaf margin: entire

  • Stem hairs: has hairs; no hairs

  • Flower color: purple; red

  • Growth habit: upright and nonwoody

  • Stem: round or oval

  • Leaf structure: simple

  • Leaf hairs: has hairs; no hairs

  • Flower diameter: dime

  • Flower symmetry: radial symetery

  • Root structure: taproot

  • Leaf stalk: none