Dioscorea The Rampant Vine
The yam is not related in any way to the sweet potato. These are herbaceous perennial stem twiners with large tuberous roots, grown for food in tropical areas, some winter-hardy with protection as far north as New York. The stems die back, but come up fast and furiously the following spring.
Most of these vines have dense, heavy foliage and are inclined to romp rampantly and grow straggly over even the largest supporting structure. Their clusters of greenish-white flowers are not particularly decorative. They are used mainly as screens on large estates and in large wild gardens. But there is one ornamental species, Dioscorea discolor, with modest manners and colorful foliage suitable for the greenhouse, and a good background plant for container gardens. Store the root indoors, cool and dry, in winter.
The yams will accept sun or shade, any moist soil with good drainage, and hard pruning. Tubers are usually spring-planted in the North. Propagation is by seeds, tuber division, and stem cuttings; and I wonder if they could be layered.
Dioscorea batatus – Chinese yam, cinnamon vine – A foliage vine better suited to Northern gardens where winter cuts back the stems and restricts growth. The three-foot tubers should be planted deep. Leaves are broad-oval, flowers sweetly spice-scented.
Dioscorea discolor – Handsome, nonhardy foliage vine for the greenhouse or container garden. Broad, heart-shaped leaves are forest green with touches of lighter green, a silvery-white midrib, and purple lining underneath.
Dioscorea villosa – wild yam, colic root – Weedy plant, suitable only for wild gardens – and large ones, at that. The large leaves turn yellow in fall. Pale flowers have no particular interest.
Family: Dioscoreaceae
Common Name: Yam
Copyright © 2012 · +Gary Antosh · Plant-Care.com
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