Marsh Dewflower Murdannia keisak

Asian Spiderwort is an invasive annual in the Spiderwort family (Commelinaceae). Native from Nepal to the Russian Far East and Temperate East Asia, Asian Spiderwort was introduced to the southeast, likely with rice seed imported from Asia. First reported in 1935 in South Carolina rice paddies, it now invades all the southeastern United States, as well as Oregon and Washington.

Asian spiderwort grows in freshwater wetlands, swamp forests, and in and on the margins of ditches, lakes, ponds, rivers, and streams. Small 3-petalled flowers, whose color may include white, pink, blue, and/or purple hues, bloom in late summer to early fall. Flowers may be solitary or in 2- to 4-flowered racemes. Fertilized flowers produce small capsules, each containing several seeds. Asian spiderworts have narrow green lance-shaped leaves up to 3 inches long, spaced alternately on succulent stems from 12 to 30 inches long. Stems are mostly emergent, prostrate, sprout roots at nodes, and can form large mats.

Asian spiderwort invades by seeds that waterfowl help spread and water-borne plant fragments that take over habitats from native plants. It is difficult to control because it establishes large seedbanks, pulled plants can quickly regenerate from small pieces left behind, and few herbicides are suitable for use in or near water.

Insects, Diseases, and Other Plant Problems:  No significant problems. Listed as invasive by the NC Invasive Plant Council. See alternative plants to the left.