October 10, 2013

By William Woys Weaver

Heirloom Vegetable Gardening by William Woys Weaver is the culmination of some thirty years of first-hand knowledge of growing, tasting and cooking with heirloom vegetables. A staunch supporter of organic gardening techniques, Will Weaver has grown every one of the featured 280 varieties of vegetables, and he walks the novice gardener through the basics of planting, growing and seed saving. Sprinkled throughout the gardening advice are old-fashioned recipes — such as Parsnip Cake, Artichoke Pie and Pepper Wine — that highlight the flavor of these vegetables. The following excerpt on heirloom Chinese yam was taken from chapter 40, “Chinese Yam.”

To locate mail order companies that carry heirloom Chinese yams, use our Custom Seed and Plant Finder. Check out our collection of articles on growing and harvesting heirloom vegetables in Gardening With Heirloom Vegetables.

A Brief History of Heirloom Chinese Yam

It is pointless to grow both sweet potatoes and yams, especially in the North or where space is limited. True yams are tropical plants in any case and cannot be cultivated outside of the Deep South without the aid of a greenhouse during the winter. Thus, the only yam that I grow is the Chinese yam (Dioscorea batatas), which is easy to cultivate and will thrive in most parts of the continental United States, at least into USDA Zone 4. It requires a winter dormancy, so it cannot be raised successfully in frost-free areas. It is also highly ornamental, for it is known among flower fanciers as the Cinnamon Vine.

Specimens of the Chinese yam were sent to France from Shanghai by the French consul in 1848. They were received at Paris under the name igname de la chine with considerable fanfare, for the plant was seen as a possible solution to the failed potato crop at the time. Since the vine produces club-shaped, deep-rooted tubers, as long as 3 feet, they were considered difficult to harvest as a field crop. In fact, the tubers are brittle and must be dug by hand to ensure they are not broken or damaged. Furthermore, the tuber sends up a rampant vine that can grow as much as 20 feet in one season. Thus, the yam must be cultivated on trellising like grapevines or pole beans. This worked against its adaptation as a commercial crop, but as a small garden vegetable it is ideal.

The first gardeners in this country to cultivate the Chinese yam were the Chinese themselves who had settled on the West Coast, primarily in California during the gold rush. It may have been this community that brought the vegetable to the full attention of American horticulturists. The 1854 Florist and Horticultural Journal (3:201–4) was careful to point out the great variety of Chinese names that were applied to the yam depending on its method of culinary preparation.

One of these, chau-tchou (as it was then written), referred to a vegetable pickle in which the shredded yam figured as a component. This word was corrupted in American English to chow-chow, a term that has lost all connection with the yam and is now used generically for any type of mixed vegetable pickle. Thus, the Chinese yam has touched American cookery in a curious, roundabout way.

While the Chinese yam failed to interest commercial growers as a substitute for the beleaguered potato, it did become a popular Victorian garden ornamental, for the bulbils were inexpensive gimmicks as premiums given away by seed houses. The promotions worked because the vine is fast growing and makes an excellent summer covering for gazebos and verandahs. Furthermore, the white cinnamon-scented flowers are powerfully fragrant, which only added to its appeal. In small gardens, the Chinese yam can double as a screen against a wall or tall fence. Because the tuber is perennial and increases in size from year to year without deterioration in quality, it can be harvested as demand requires. Harvesting is normally undertaken in November before the ground freezes because the tubers grow most late in the season and store well for many months over the winter.

The vine itself produces hundreds of edible bulbils at the leaf axils, and these should be harvested before frost. The bulbils resemble miniaturized potatoes, and those that are not eaten can be planted to replace harvested tubers, thus ensuring a continuous supply from year to year.

While this is a true yam, it is unlike any yam American cooks are likely to find in a typical supermarket. The flavor reminds me of a blend of potato and butternuts, although physically the mature tuber resembles a long, swollen, and somewhat hairy manioc root, and is so illustrated in Vilmorin (1885, 596–97). The potato-like skin is green underneath and should be pared off when preparing the yam for cookery; otherwise, it lends itself to any recipe calling for mealy potatoes, since the white, milky flesh becomes soft and flaky once cooked. The root can also be shredded like a daikon radish and marinated in vinegar. In pickles, it should be raw packed to maintain crispness.

The bulbils make an interesting addition to rice and bean dishes, or they can be used in stuffing, like chestnuts. The rich, nutty flavor is pleasant, and I am surprised that the Chinese yam is not more readily available in our markets.

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Illustration Courtesy William Woys Weaver. Photo By Fotolia/monamakela.com.