Simple, smooth-edged leaves grow opposite or whorled on stiff, 4-6-sided stems. Swamp loosestrife (Decodon verticillatus) arches out from shorelines, has mostly whorled leaves and flowers in well-separated leaf axils. With this bacterial disease, dark, black and sharply rimmed spots appear on the lower and upper leaf side. Remarks: Other species of Lythrum that grow in the United States have 1-2 flowers in each leaf-like inflorescence bract and eight or fewer stamens compared to L. salicaria, which has more than two flowers per bract and typically twelve stamens per flower. Purple loosestrife, a beautiful garden plant with an aggressive nature, was first introduced into North America in the early 1800s. Flowers in clusters of 3–5 in upper leaf-axils forming spike-like panicles, subsessile; hypanthium cylindric, 4.5–5 mm long, 1.5–2 mm diam., appendages 5 or 6, subulate, 2–3 mm long; sepals 5 or 6, triangular, c. 1 mm long; petals 5 or 6, spreading, ovate, 8–10 mm long, … The leaves first turn brown and then dry up. Lythrum plants were brought to North Dakota for flower gardens because of their striking color, ease of growth, winter hardiness, and lack of insect or disease problems. The plant was sold in North Dakota by its genus name Lythrum for at least 50 years. Lythrum salicaria Loosestrife family (Lythraceae) Description: This perennial plant is 2-5' tall, branching frequently below the inflorescence. Nevertheless, Lythrum salicaria can be affected by leaf spot disease. Lythrum salicaria, commonly called purple loosestrife, is a clump-forming wetland perennial that is native to Europe and Asia. Leaves are opposite, (sometimes whorled), nearly linear, and attached to four-sided stems without stalks. The leaves are usually opposite, less often whorled in 3's; some of the upper leaves in the inflorescence may be alternate. (Lythrum salicaria) Photo credit: S. Kelly Kearns. The specific epithet salicaria means willow-like; it refers to the shape of the leaves of this plant. It can be safely taken by people of all ages and has been used to help arrest diarrhoea in breast-feeding babies. ... solitary flowers in separated leaf axils, paired lower leaves and alternate upper leaves. Purple loosestrife (Lythrum salicaria), a beautiful but aggressive invader, arrived in eastern North America in the early 1800’s.Plants were brought to North America by settlers for their flower gardens, and seeds were present in the ballast holds of European ships that used soil to weigh down the vessels for stability on the ocean. The disease is favored primarily by high soil moisture and rain. The purple loosestrife plant (Lythrum salicaria) is an extremely invasive perennial that has spread throughout the upper Midwest and Northeastern United States.It has become a menace to the native plants in the wetlands of these areas where it chokes out the growth of all its competitors. Margins are smooth. The stems are variably hairy, becoming woody and glabrous below. It is believed to have been first introduced into the U.S. from seed contained in ships’ ballast, and it became established in certain estuaries in the northeastern states by the early 1800s. The Arrival. Latin name: Lythrum salicaria Family: Lythraceae (Loosestrife Family) Medicinal use of Purple Loosestrife: Purple loosestrife is an astringent herb that is mainly employed as a treatment for diarrhoea and dysentery. Lythrum salicaria Purple loosestrife, a regulated Class B noxious weed, is a 6-10-foot-tall perennial that grows on lakes and waterways throughout King County.