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Wildlife Branch


Species At Risk

Western Spiderwort Fact Sheet

Provincial Range MapWestern spiderwort was designated as Threatened by COSEWIC in 1992 and likewise under the Manitoba Endangered Species Act in 1994. It is a perennial with stout, fleshy roots, and flowers that are generally blue or purple, but occasionally pink or white. Flowers appear in late June to early July, and are pollinated by a variety of insects, most commonly by sweat bees. In Manitoba, the Western spiderwort grows on sandy soils, in open to partially stabilized dune systems. The largest population of Western spiderwort in Canada occurs in the Routledge Sandhills; a smaller population is found in the Lauder Sandhills, northeast of Melita.

Threats include changes in land management practices, especially burning and grazing regimes. Western spiderwort requires open sand to thrive, and continued fire suppression allows vegetation to encroach, stabilizing dune systems and degrading spiderwort habitat. The continued spread of weedy invasives, especially leafy spurge, is also a major concern for the long-term health of Western spiderwort populations. Petroleum exploration and all-terrain vehicle traffic in southwest Manitoba pose significant threats to spiderwort habitat. An Ecologically Significant Area protects part of the Routledge site, and a portion of the Lauder site is owned by the Manitoba Habitat Heritage Corporation, who purchased the site in order to conserve habitat for this and other species.

For more information on the western spiderwort view the Manitoba's Species at Risk brochure (PDF document, 210 KB).

North American Range Map