Plants of the Eloise Butler Wildflower Garden

Winged Loosestrife is an erect native perennial growing 3 to 5 feet in height. The stems can branch from the base, are 4 angled with the ridges of the angles running vertically - hence 'winged'. Stems are without hair. There are two varieties of this species. Var. alatum has stems usually less than 3 feet high. Var. laceolatum has stems usually higher than 3 feet. Var. alatum is found in Minnesota.

The leaves are alternate in the upper half of the stem, opposite in the lower half, without teeth or hair, somewhat thick and rigid. Var. alatum has leaves that are ovate to oblong with bases rounded to nearly heart-shaped. Var. laceolatum has leaves lanceolate to linear, bases gradually narrowing.

The inflorescence is a terminal spike (raceme) that can be up to 16 inches high, with axillary spikes rising stem branches. Flowers appear alternately on the spike at the base of a green leafy bract.

Flowers: The pale purple flowers are 1/2 to 1 inch wide, are 6-parted and have a wrinkled appearance; the petals have a deep purple central vein. The calyx tube is green, longer than the petals, with noticeable purple veins and with 6 very narrow teeth or appendages at the tips. The tube may have a very short stalk but they are usually stalkless. There are 6 stamens with a nectary at the base of the ovary, a single greenish style.

Seed: Fertile flowers produce a seed capsule that is surrounded by the remains of the calyx. Each capsule contains numerous small tan oblong seeds that can be blown a short distance by the wind and these will float on water for further distribution.

Habitat: Winged Loosestrife occupies the aquatic edges of streams, lakes, swamps, etc. It grows from a rhizomatous root system.

Names: The genus Lythrum is believed to be derived from the Greek word lythron, for 'blood' and referring to the color of the flowers. The species alatum means 'winged' referring to the vertical ridges on the stem angles. The author name for the plant classification, ‘Pursh’ refers to Frederick Traugott Pursh (1774-1820) German-American botanist who wrote A Systematic Arrangement and Description of the Plants of North America, and was the botanist who catalogued and described the plants brought back by the exploring expedition of Lewis and Clark. Pursh was disliked by American botanists because he took some of these plants to New York with him and later to London treating them as his own property. He did the same years later with much material collected by Thomas Nuttall, writing it up with no credit to Nuttall.

Comparisons: In moist areas you may encounter the Purple Loosestrife, Lythrum salicaria, which has flowers that are also purplish, but the stems are not winged and leaves downy and less rigid. This is the only other species of Lythrum normally found in Minnesota.