Central to south China
Forms dense floating mats of intertwined stems over water surfaces, shading out native submersed plants and competing with native emergents (K. C. Burks, Florida Department of Environmental Protection, personal observations).
Herbaceous trailing vine with milky sap. Stems hollow, to 3 m (9 ft) long or more, rooting at nodes, floating in aquatic situations. Leaves alternate, simple, with glabrous petioles 3-14 cm (1-6 in) long; leaf blades generally arrowhead shaped but variable, glabrous or rarely pilose, to 17 cm (7 in) long, with tips pointed; blades held above water when stems floating. Flowers showy, funnelform like morningglory blooms, solitary or in few-flowered clusters at leaf axils; petals white or pink-lilac. Fruit an oval or spherical capsule, woody at maturity, about 1 cm (1/2 in) wide, holding 1-4 grayish seeds, these often short-hairy. (Langeland and Burks, 1998)
Two basic forms (with many cultivars of each) recognized worldwide for this species: “red,” with red-purple tinged stems and pale pink to lilac flowers; and “green,” with fully green stems and white flowers—all “races” observed in Florida exhibiting the same growth habit. (Langeland and Burks, 1998)
Introduced repeatedly to Florida waters since 1979, despite its state and federal listing as a prohibited plant and noxious weed (R. Kipker, Florida Department of Environmental Protection, unpublished data). Popular among some recent immigrants as a common potherb from the homeland (T. Q. Ngo, Vietnamese Community of Florida, Pinellas Park, 1995 personal communication), and has been studied in Florida as a vegetable crop (e.g., Bruemmer and Roe 1979, Snyder et al. 1981).
Herbarium specimens documented so far only from the Tampa Bay area (Wunderlin et al. 1995), where it may now be found cultivated under specially permitted quarantine conditions for out-of-state sale.
Chemical control by 2,4-D, glyphosate, imazapyr, triclopyr. Another option would be hand pulling. Proceed with caution as to not break up plant into small pieces.