Ohio State University Extension Bulletin 866-98

Identifying Noxious Weeds of Ohio

Bulletin 866-98


Purple Loosestrife
(Lythrum salicaria)

Habitat: wet meadows, flood plains, wetlands, ditches

Life cycle: perennial

Growth Habit: usually 2- 4 feet tall, but may reach up to 10 feet in nutrient-rich habitats

Leaves: Opposite or whorled, 1.5-4 inches long with smooth margins, lacking petioles. Lower leaves have downy hairs and clasp the stem.

Stem: stiff, 4-sided, woody at the base

Inflorescence: July to early September. Long spikes of rose or purple flowers, each with 4-7 wrinkled petals.

Similar plants: Flowers of native loosestrife are more widely spaced along the stem than those of purple loosestrife.

The problem is.... purple loosestrife is a strikingly beautiful plant that has escaped from cultivation. (It is an introduced species.) This plant invades wetland habitats, crowding out native plants that are important food sources for wildlife. A single stalk of purple loosestrife can produce 300,000 seeds. Purple loosestrife also spreads vegetatively. Cultivated varieties of this plant, sold in nurseries, are supposedly less aggressive, but still may present a risk.

Purple loosestrife

Purple loosestrife crowds out native plants that provide food for wildlife.

Purple loosestrife


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