The Western Aquatic Plant Management Society

Description and Variation

Garden loosestrife is an erect rhizomatous perennial that may attain a height of one meter or more. Both the stems and the leaves are softly hairy. Lance-shaped leaves, 8-12 cm long, occur on the stem in an opposite or whorled arrangement. The leaves are dotted with black or orange glands. The yellow, primrose-like flowers occur in a cluster at the top of the plant. Each flower has five petals and a calyx with reddish-brown margins. The fruit is a dry capsule.

Economic Importance

Beneficial: Flavanol glycosides extracted from Lysimachia vulgaris var. davurica are used in Chinese folk medicine for the treatment of high blood pressure.

Detrimental: The apparent ability of garden loosestrife to invade and establish itself in freshwater wetlands threatens the native character of this natural resource. Control of this species is complicated by two factors: 1) the species is a rhizomatous (stoloniferous) perennial, and 2) it inhabits environmentally sensitive wetland sites. Therefore, from an economic and environmental perspective, it is advisable to prevent the expansion of garden loosestrife in the western states.

Habitat

Lysimachia vulgaris occurs in moist habitats, such as fens, wet woods, lake shores, and river banks. It has also been planted as an ornamental and used for landscaping purposes as illustrated by the photograph to the right.

Geographic Distribution

Lysimachia vulgaris is a native of Eurasia, where it occurs in fens, wet woods, lake shores, and river banks almost throughout Europe. In North America, it is naturalized in parts of Quebec, Illinois, Ohio, Kentucky, West Virginia, and Pennsylvania. The species appears to be increasing in the Ohio River Valley (Cusick 1986). In Washington, wild populations of garden loosestrife are currently known from Lake Sammamish and Lake Washington and eastern Washington sites.

History

The only herbarium collection of Lysimachia vulgaris from Washington was made in 1978 by Dr. Bastiaan Meeuse. It is stored at the University of Washington herbarium. The collection comes from the east-northeast corner of Lake Washington near Juanita Junction. Extensive established populations along the shores of Lake Sammamish were observed in 1991.

Growth and Development

Lysimachia vulgaris is a rhizomatous or stoloniferous perennial that appears to remain in the vegetative stage for some time prior to blooming. According to Cusick (1986), the presence of a flowering specimen indicates it has been in an area for some years.

Reproduction

Garden loosestrife spreads by seeds and rhizomes (stolons). The species flowers from July to September.

Response to Herbicides

Response to herbicides is not currently known. Applications of Rodeo® to the Lake Sammamish populations will be monitored for effectiveness.

Response to Cultural Methods

Garden loosestrife has been covered with black plastic at least one site on Lake Sammamish. This may be effective on very small populations or serve as a suppression tool where herbicides are not desired. Other alternatives have not been studied. Since the species has extensive rhizomes, handpulling or digging would be limited to very small infestations.

Biocontrol Potentials

No biological control agents are presently known. No research is currently being conducted.

References

Bailey, L.H. and E.Z. Bailey. 1976. Hortus Third. Macmillan Publishing Co., Inc. New York.

Brockett, B.L. and T.S. Cooperrider. 1983. The Primulaceae of Ohio. Castanea. 48: 37-40.

Cusick, A.W. 1986. Distributional and taxonomic notes on the vascular flora of West Virginia. Castanea. 51: 56-65.

Coffey, V.J. and S.B. Jones, Jr. 1980. Biosystematics of Lysimachia section Seleucia (Primulaceae). Brittonia. 32: 309-322.

Duppstadt, W.H. 1977. Some new state records and other plant finds in West Virginia. Castanea. 42: 257-258.

Gleason, H.A. 1952. The New Britton and Brown Illustrated Flora of the Northeastern United State and Adjacent Canada. 3: 38-39.

Tutin, T. G., V. H. Heywood, N. A. Burges, D. M. Moore, D. H. Valentine, S. M. Walters, and D. A. Webb. 1976. Flora Europaea, vol. 3: 26-27. Cambridge University Press, Cambridge.

Yasukawa, K and M. Takido. 1988. Quercetin 3-Rhamnosyl (1--2) galactoside from Lysimachia vulgaris var. davurica. Phytochemistry. 27: 3017-3018.

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This page was last updated 06/16/2004