Synonym(s): Benghal dayflower
Duration and Habit: Perennial Herb
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Stem is ascending and can be over 3 ft. (1 m) long. Leaves are alternate, parallel-veined like a lily leaf, 1.2-2.8 in. (3-7 cm) long, and can be about twice as long as wide. The leaf sheaths often have reddish hairs where the leaf meets the stem. This is a distinguishing characteristic. Possesses both above- and below ground flowers. Aboveground flowers are lilac to blue and very small and are present from the spring into the fall. The two prominent upper petals are only 0.1-0.2 in. (3-5 mm) across and are on thin pedicels, and the lower petal is inconspicuous and usually white. Underground flowers, which grow on burrowing rhizomes, are white and very small. They do not open.
Native Lookalikes: Several native species of spiderwort (Tradescantia spp.) or dayflowers (Commelina spp. and Tinantia anamola) may be confused with tropical spiderwort. However, the spiderworts have three large petals while the dayflowers (Commelina spp.) have two prominent petals and a third less prominent petal. Tropical spiderwort is called a spiderwort but note it is in a dayflower genus, and hence it has the typical dayflower flower structure. The flowers of our native dayflowers are much larger compared to tropical spiderwort, and their leaves lack the reddish hairs on the leaf sheaths of tropical spiderwort. Two likely natives to confuse with tropical spiderwort are white-mouth dayflower (Commelina erecta) and false dayflower (Commelinantia anomala or Tinantia anomala).
white-mouth dayflower (Commelina erecta)
Note linear leaves, much larger upper petals with short pedicels. In addition, lacks the reddish hairs on the sheath, although not visible in this photo.
false dayflower (Commelinantia anomala or Tinantia anomala)
As with the white-mouthed dayflower, note linear leaves, much larger upper petals with short pedicels. Also lacks reddish hairs on the sheath, although not visible in this photo.
Ecological Threat: Tropical spiderwort forms, dense, pure stands, smothering out other plants, especially low-growing crops. It has been reported recently as a problem in cotton in Alabama. In pastures, it grows rapidly over desirable grasses and legumes, competing with them for light and nutrients. In rice and other lowland crops it may be almost subaquatic withstanding flooding and waterlogged conditions, but they can also be found in cultivated lands, field borders, gardens, grasslands, roadsides, and waste places, and can become the dominant species in pastures.
Biology & Spread: The plants reproduce by seeds, stolons, and rooting at nodes of stems. One plant can produce as many as 1600 seeds.
History: Was first found in the United States in 1963.
U.S. Habitat: Benghal dayflower invades areas with moist soil including roadsides, grasslands and other disturbed areas.
U.S. Nativity: Introduced
Native Origin: Asia and Africa
U.S. Present: AL, CA, FL, GA, HI, LA, NC
Distribution in Texas: Currently not found in Texas.
If you believe you have found tropical spiderwort, please report this species.
False dayflower (Commelinantia anomala or Tinantia anomala)
Property managers and cooperators may use these strategies:
Cultural Control: Plants readily root at the nodes of the creeping stems, especially when cut or broken, making these weeds difficult to control in field areas. Sections on the soil surface root readily during rainy weather or in the shade of crop plants.
Chemical Control: University of Florida tests conducted in 2000 showed that Command and Spartan used in combination or alone were effective April to early June, but effectiveness trailed off later in the season. Methods Development has found that 46 brands of herbicide are labeled for use on dayflower. However, farmers in Florida have not been able to control tropical spiderwort effectively with chemicals. Control with herbicides is difficult because many seeds germinate after the initial flush of summer weeds and part of the seeds are produced underground.
Biological Control: None is known.
Domestic Programs Pest Evaluation. Arthur E. Miller, USDA-APHIS-PPQ, AERO, Raleigh, NC. November 26, 2001.
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