Americanized Chinese Yam Gardens: Exotic Yams for Taming and Tasting

Summary: Americanized Chinese yam gardens nestle air, Chinese and greater yams into naturalized courtyard and indoor niches that nurture nutritious vegetables.

Chinese yam (Dioscorea polystachya) plants bear aerial tubers, known as bulbils; Botanischer Garten KIT (Karlsruher Institut für Technologie), Karlsruhe, Baden-Württemberg state, southwestern Germany; Aug. 30, 2009: H. Zell, CC BY SA 3.0, via Wikimedia Commons

Americanized Chinese yam gardens allow arborists, gardeners, naturalists and stewards to address recommended daily allowances in vegetables for family, friends, neighbors and themselves and for fresh food markets and local food pantries.

No province, state or territory in Canada, Mexico or the United States bans the production or the proliferation of the native of China and southeast Asia. Chinese yams, introduced into the United States as food plants in the nineteenth century, can be considered weeds for climbing over and competing with native vegetation. They dominate native vegetation by multiple means as aerial, fleshy, tuberous reproductive structures called bulbils, whose partial destruction does not deter germination, and as viable seeds.

Propagation in disturbed, natural and wild landscapes ensues generally from germination of aerial bulblets since female-flowering Chinese yams exist almost exclusively in cultivated North American landscapes.

Master arborists, master gardeners, master naturalists and tree stewards on organized invasive weed pulls rarely find seedlings since naturalized escapes from cultivation biologically favor male-flowering yams.

The mature Chinese yam gets female and male forms of its herbaceous or somewhat woody vine, whose twining growth habit always goes from left to right. Semi-fleshy, semi-woody, tuberlike, 13.12-foot- (4-meter-) long stems and 5-pound (2.27-kilogram), 3.28-foot- (1-meter-) long roots handle cold hardiness to minus 0.4 degrees Fahrenheit (minus 18 degrees Celsius). Aerial tubes called bulbils, 0.28 to 1.18 inches (7 to 30 millimeters) long, initiate reproduction from the axil unions of leaves with branching or unbranched stems.

Americanized Chinese yam gardens join bronze tints on new leaves to otherwise green, hairless, nine- to 13-veined, oval to heat-shaped foliage on stalks longer than blades.

The 1.58- to 3.15-inch- (4- to 8-centimeter-) long foliage knows alternate and three-whorled placements, as upper foliage, and opposite positions, as lower leaves, around twining stems.

Chinese yams, scientifically called Dioscorea polystachya (Dioscorides' [A.D. 40?-90?] many grain ears), looks like arrowheads at foliar bases and like long, tapered points at foliar tips. The common name cinnamon vine mentions the fragrance of green-yellow, stalkless flowers on female- or male-flowering Chinese yams, also commonly called air yams and potato vines. Male-flowering Chinese yams need three petals, three sepals and three stamens for every flower nestled in groups of three along branching, flower-clustered, pyramid-shaped inflorescences called panicles.

Female-flowering yams, each with one pistil with a three-branched style, two modified leaves called bracts, three petals and three sepals, rarely occupy Americanized Chinese yam gardens.

Asia-grown perennials produce three-angled, 0.79- to 1.57-inch- (2- to 4-centimeter-) long, 0.79-inch- (2-centimeter-) wide capsules, each with three to six membrane-winged, yellow-brown, 0.39-inch- (1-centimeter-) wide seeds.

Two weeks after quitting leaf axils and two weeks at temperatures of 68 degrees Fahrenheit (20 degrees Celsius) respectively quicken the germination of bulbils and seeds. Wildlife and wind rank as main dispersal means for June- through August-blooming Chinese yams, described by Nikitovka-born Russian botanist Nikolai Stepánovich Turczanínow (May 1796-Jan. 7, 1864). They spread fellow Dioscoreaceae family members, air or potato yams and greater, water or white yams, respectively designated weeds in Alabama and Florida and in Florida.

Courtyard and indoor Americanized Chinese yam gardens with air, Chinese and greater yams treat their caregivers to fragrant scents, subtropical and tropical colors and tasty vegetables.

edible Chinese yam roots; Chinese market, San Francisco, California; Jan. 29, 2015: Maor X, CC BY SA 4.0, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Chinese yam (Dioscorea polystachya) plants bear aerial tubes, known as bulbils; Botanischer Garten KIT (Karlsruher Institut für Technologie), Karlsruhe, Baden-Württemberg state, southwestern Germany; Aug. 30, 2009: H. Zell, CC BY SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Dioscorea_polystachya_003.jpg?uselang=fr

edible Chinese yam roots; Chinese market, San Francisco, California; Jan. 29, 2015; Maor X, CC BY SA 4.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Roots_of_chinese_yam_(Dioscorea_polystachya).jpg?uselang=fr

For further information:

Dickinson, Richard; and Royer, France. 2014. Weeds of North America. Chicago IL; London, England. The University of Chicago Press.

"Dioscorea polystachya Turcz." Tropicos® > Name Search.
Available @ http://www.tropicos.org/Name/11000612

Turcanínow, Nikolai Stapánovich. 1837. "198. Dioscorea polystachya." Bulletin de la Société Impériale des Naturalistes de Moscou, tome 10, numéro 7: 158.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/41314106

Weakley, Alan S.; Ludwig, J. Christopher; and Townsend, John S. 2012. Flora of Virginia. Edited by Bland Crowder. Fort Worth TX: BRIT Press, Botanical Research Institute of Texas.