College of Agriculture and Life Sciences

Crop Science Department

Invasive Weed Fact Sheet

Stratford Kay and Steve Hoyle

 Asian Spiderwort

Murdannia keisak (Aneilema keisak)

Asian spiderwort, a wetland and shallow-water annual in the dayflower family, is an introduction from eastern Asia, which has become established and naturalized from southeastern Virginia to Florida. Monoculture growths of spiderwort occur in heavy shade to sunny environments in damp areas, and dense floating mats may form wherever there is standing water. Reproduction is by fragmentation and seed production. This plant has become highly invasive in marshes, swamps, ditches, creek and riverbanks, and around ponds and lakes, rapidly crowding out desirable native herbaceous vegetation. Distribution in North Carolina is statewide.

Stems tend to be weak and sprawling and root extensively wherever a node touches damp soil. In dense growths, the stems may grow to 18 inches in height. Stem fragments root readily wherever moisture is abundant and can be spread to new sites by disturbances, including water movement. The leaves grow up to 3 in. long, are alternate, lance-shaped, and have parallel veins. Leaf bases form a sheath wrapping around the stem. Flowers have three pink to lavender petals, are slightly over 1/2 inch in diameter, and are attached on short stalks to the leaf axil, either solitary or in groups of 2 to 4. Flowering occurs in late summer through early fall. Each flower produces a capsule containing several small seeds.