Family: Convolvulaceae (Morning-Glory Family)
Duration and Habit: Perennial Vine
As a floating herbaceous vine, it has long, branching stems containing a milky sap, with roots extending from leaf nodes. Leaves are alternate, simple, and generally arrowhead-shaped. They are 2 - 6 inches long and 0.75 - 2.25 inches wide. Petioles are 1 - 4 inches long. Flowers are white to lavender and funnel-shaped (morning-glory-like). Fruit is oval to spherical, and is 0.5 inches long and woody when mature. Fruit capsules contain 1 - 4 seeds. Water spinach can grow at a rate of 4 inches per day, producing 84 tons of fresh weight biomass per acre in 9 months. Branching stems can reach 70 feet in length.
Ecological Threat: Water spinach has created a variety of problems for fishery management, navigation, irrigation, and ecology of native plants in a number of areas around the world (Harwood and Sytsma 2003). Floating stands can cover the water surface shading native plants and effectively competing with native plant species (Langeland and Burks, 2000). In the Philippines water spinach is considered the second greatest problem plant (Holm et al, 1979; Gangstadt, 1976; Cook, 1990).
According to the Risk Assessment for Water Spinach (Ipomoea aquatica) in Texas (Earl Chilton II, TPWD), water spinach has been cultivated in Texas for at least twenty years. Some people in the Houston area claim cultivation began in the mid-1970s with the influx of Southeast Asian refuges resulting from the war in Vietnam. During most of that time regulators were unaware of the growing industry. In 1989, Texas Parks and Wildlife Department was given legislative authority to regulate aquatic plant species, and water spinach was placed on a list of prohibited harmful or potentially harmful aquatic plants. At that time TPWD was unaware of the growing water spinach production industry, and growers were unaware of TPWD regulations. In 2003, TPWD became aware of water spinach cultivation facilities in Rosharon, Texas near Houston. At that time there were in excess of 60 growers in the area. Many of the growers were Cambodian-Americans. Primary consumers of the product were Vietnamese-Americans and Chinese-Americans. As a result of there being no evidence of establishment after approximately 30 years of commercial cultivation, TPWD modified regulations regarding water spinach in 2005 making production legal with an exotic species permit, and possession for personal consumption legal.
Biology & Spread: Water spinach may reproduce either vegetatively or by seed production. In its native India it flowers from late October to early April. In Florida, flowering occurs during warmer months (Dressler, et al., 1987). Seed production ranges from 175-245 per plant (Patnaik, 1976). There is evidence that germination takes place more readily on land than under water (Palada and Crossman 1999, Edie and Ho 1969, Patnaik 1976). However, reproduction is primarily by fragmentation (Patnaik, 1976; Edie and Ho, 1969; Schartz and Schmitz, 1990). Nodes of existing stems can easily root and establish new plants. Both stem fragments and seeds are easily transported by water to become established in new areas. Patnaik (1976) reported that the branches, with roots at each node, could each grow into independent plants.
History: First introduced in 1979 in Florida, and continues to be introduced by immigrant communities who use it as an herb rich in iron.
U.S. Habitat: Requires warm, humid conditions. A primary invader of man-made aquatic environments such as canals and ditches, and may potentially invade rice fields. Also found in natural wetlands, lakes, and river shorelines.
U.S. Nativity: Introduced to U.S.
Native Origin: China - cent. to south. (NatureServe Explorer) ; Not Found (Bailey, L.H. and E.Z. Bailey, Hortus Third: A Concise Dictionary of Plants Cultivated in the United States and Canada, MacMillan Publishing Co., Inc., New York , (1977).)
U.S. Present: FL, HI, PR
Distribution: Currently only reported in the wild in Florida and Califonia. Continues to be sold in the Houston area, but naturalized reproducing populations have yet to be found in the area.
List All Observations of Ipomoea aquatica reported by Citizen Scientists
American lotus (Nelumbo lutea), White water lily (Nymphaea odorata), Floating bladderwort (Utricularia radiata)
Avoid introducing this plant to local waterways. Glyphosate is effective when applied to plants in dry ditches, but will affect native species as well. 2,4-D is more selective, but little is known about is effectiveness.USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS. MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.
Cook, C.D.K. 1990. Origin, autecology, and spread of some of the world's most troublesome aquatic weeds. p. 31-38. In: A.H. Pieterse and K.J. Murphy (eds.), Aquatic Weeds: The Ecology and Management of Nuisance Aquatic Vegetation. Oxford University Press, New York.
Edie, H.H. and B.W.C. Ho. 1969. Ipomoea aquatica as a vegetable crop in Hong Kong. Economic Botany. 23: 32-36.
Gangstadt, E.O. 1976. Potential growth of aquatic plants in Republic of the Philippines and projected methods of control. Journal of the Aquatic Plant Management. 14: 10-14.
Holm, L., J.V. Pancho, J.P. Herberger, D.L. Plucknett. 1979. A Geographical Atlas of World Weeds. John Wiley and Sons, New York. 391 pp.
Langeland, K.A. and K.C. Burks. 2000. Identification and Biology of Non-Native Plants in Florida's Natural Areas. Gainesville: University of Florida, Institute of Food and Agricultural Sciences (IFAS). 166 pp. http://plants.ifas.ufl.edu/identif.html Accessed 5/2/03.
Palada, M.C. and S.M.A. Crossman. 1999. Evaluation of tropical leaf vegetables in the Virgin Islands. p. 388-393. In: J. Janick (ed.), Perspectives on New Crops and New Uses. ASHS Press, Alexandria, VA.
Patnaik, S. 1976. Autecology of Ipomoea aquatica Forsk. Journal of the Inland Fisheries Society of India. 8: 77-82.
Schardt, J. D., and D. C. Schmitz. 1990. 1990 Florida aquatic plant survey report. Unpublished report, Florida Department of Natural Resources, Tallahassee. 89 pp.
The Quiet Invasion: A Guide to Invasive Plants of the Galveston Bay Area. Lisa Gonzalez and Jeff DallaRosa. Houston Advanced Research Center, 2006.
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