Asian spiderwort (murdannia keisak)
Photo credit: Bobby Hattaway 2011, discoverlife.org 

Asian Spiderwort

(Murdannia keisak)

Species at a Glance

Asian spiderwort is a shallow water succulent plant and member of the dayflower family. It produces long trailing shoots that root at nodes, reaching heights of approximately 46 cm (18 in). It can be found in water depths of up to 7.5 cm (3 in).

Identification

Leaves: Alternate leaves are 2.5-7.5 cm (1-3 in) long and have parallel veins, long narrow blades, and oblong bases that wrap around the stem.

Flowers: Growing from the leaf axils in groups of 2-4, flowers consist of three pink to violet petals and three small, thin green sepals. Each flower lives for only one day and blooms from late August to October.

Fruit/Seeds: Each flower produces a capsule containing thousands of very small seeds.

 

Stems/Roots: Weak and sprawling stems are 30-76 cm (12-30 in) long and root extensively wherever a node touches damp soil.

Similar Species

Asian spiderwort may be confused with other species in the dayflower family such as the climbing dayflower (Commelina diffusa), which has three bright blue petals on each flower, and Whitemouth dayflower (Commelina erecta), which has bright blue flowers with only two petals.

Habitat

Most common in coastal marshes, Asian spiderwort can also be found inland in freshwater marshes, ditches, creeks, rivers, swamps, bogs and along the edges of ponds, lakes, and streams.

Spread

After escaping cultivation, Asian spiderwort established in the wild where it continues to spread by both seeds and fragmentation. Seeds, stems, and roots can be carried by wildlife and flooding to new locations where the plant can start new populations.

Distribution

Native to China, Japan, Korea, and Tibet, the earliest record of Asian spiderwort in the United States dates back to the 1920s and early 1930s when it was thought to have been brought to South Carolina mixed in rice seeds imported for growing. It is now found in all coastal states from New Jersey to Louisiana, inland in Arkansas, Kentucky, and Tennessee, and in the Pacific Northwest in Washington and Oregon.

 

Note: Distribution data for this species may have changed since the publication of the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016), the source of information for this description.

Environmental Impacts

This aggressive plant establishes itself in freshwater wetlands and forms dense mats that crowd out native vegetation and clogs waterways.