This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
Still a few genera are found in temperate climates. Our black bryony, of the English hedge-rows (Tamus communis), is one, though, to be sure, it is no great bargain; for though its fruit is red and succulent, its root is very acrid. Yet all this is nothing. The Solanum tuberosum, our cultivated potato itself, is, it is well known, quite a poisonous plant in a state of nature. Culture may readily ameliorate all this acridity; and if we can credit all that has been stated in favor of the new importation, has far more than done so. Certain it is that it holds the same place in the North of China, and is found to comprise the same nutritive properties, as the potato in this country. Mr. Henderson, a Devonshire horticulturist, by whom it is introduced amongst us, designates it, in foot, a potato, just because with us ordinary yams cannot be grown except by means of stoves. M. de Montigny has stated that the Chinese, at taking up the crop, set aside all the smaller roots for seed. It is well known that this is a practice now preferred by our market gardeners to cutting large potatoes into sets, simply because they like a juicy set. and find the immature tuber most favorable for their purpose.
This is, so far, fortunate in the case of the new potato, admitting, as we shall presently learn, of its rapid and unlimited propagation; for the Chinese place these tubers first in pits or trenches for preservation (and they are said to keep far better than potatoes all the winter, covered with straw and a coating of earth, never losing weight or developing exhaustive shoots); and in spring, being laid out horizontally in beds of prepared mould, they speedily ger-minate, and send forth long trailing stems, like those of the kidney bean. In six weeks time the stems attain six feet in length, and are planted out afresh, and layered - that is, the plant is laid lengthwise along a slight furrow, on the top of a. ridge, and all except its leaves covered over with earth. Immediately after rain, it begins to take root, or in dry weather is watered until it grows; and in fifteen or twenty days it produces tubers, throwing out at the same time long trailing stems, which are, however, carefully prevented from taking root, and producing a second set of tubers, to the prejudice of the main crop. Sometimes the shoots are simply pegged down, without removal of the plant, over the sides of the ridge on which it grows, at intervals of six or eight inches, and there striking root, throw out tubers.
By this means it is stated that immense quantities of roots, of the size of our early kidney potatoes of the garden frame, are raised on comparatively small pieces of land. To obtain large-sized tubers, small ones, or portions of large, are planted in ridges, at from ten to twelve inches apart; and the plants being allowed to grow freely in autumn, the tubers thus attain an average weight of one pound and upwards. This is the plan which has been pursued at the Museum of France, the only place in Europe where the new plant has hitherto been cultivated. And in the report of M. Pepin on the subject, it is conceived that a few years must yet elapse ere we shall know to what extent the roots left in the ground will acquire weight and bulk, and how long they may remain in the sod without deterioration of their quality; for it is one of their peculiarities that, like the roots of the Jerusalem artichoke, they will remain in the ground several years, acquiring weight, size, and nutriment, instead of deteriorating, and requiring, in fact, little or no cultivation, whilst yielding at all seasons aliment within the reach of every one. A tuber taken up at the end of three years, in France, had its cellular tissue healthy to the centre, where it was neither hard nor woody.
A root was also preserved in a cellar from Oct., 1852, to 30th May, 1853, without any development of shoots, unchanged, without loss of weight. and might have been kept so nearly throughout the year, which is not the case with either the common or sweet potato, since they always sprout in spring. Moreover, Decaisne believes this Dioscorea richer in nutrition than, and superior in quality to the potato; its roots are white as snow, having no visible fibre or woody matter within, and, cooked by steam or roasted, look and taste like the best potatoes. This is not their whole culinary advantage, either; for two pieces of tubers, the size of a hen's egg, of Dioscorea and Batate blanche, being put into boiling water simultaneously with a Dutch potato of similar size, were "done " in ten minutes, whilst the Dutchman took twenty.
The strongest point, perhaps, in favor of the new candidate for cultivation is the fact it will grow best on sandy downs usually considered barren, and may be regarded as a messenger sent by Providence to reclaim our most extensive wastes, in advance of the onward strides of population. It is, indeed, pointed out by its partisans as a probable means of converting waste land to a useful purpose, as well as profit Neither does it require strong or liquid manure - items expressly forbidden in its culture; but pits filled with earth and a mixture of decayed manure, and treatment similar to that bestowed upon asparagus, are strongly recommended as the means of producing the most abundant crop, the question of the expense of manual labor being asserted to be of little consequence, compared with the remunerative results.
The flesh is white, very mealy, and equal in quality to the potato. The stems of the plant are twining, and grow to the height of 4 to 6 feet, the leaves heart shaped, the flowers very small, dioecious, of a yellowish color, and produced from the axils of the leaves. If planted in April, the Dioscorea will by the ensuing October produce tubers 15 to 20 inches long, slightly swelling at the ends, being club form, and weighing from 10 to 14 ounces each. Of all the plants which have been proposed as substitutes for the potato, the Dioscorea is the only one which presents claims sufficiently strong to sustain the competition, for if the Dioscorea can enter into a successful competition with the Potato for the quality of its tubers, it can most assuredly do so by the quantity of its crops. The plants when placed at a distance of 12 inches by 8, will, according to the authority of Professor Decaisne and M. Paillet, yield about 290 cwt., (per acre, we suppose,) or 14) tons when growing from April to October, or 48 tons if allowed to remain two seasons in the ground, that is, to occupy the ground from April of one year till October of the subsequent one.
In the latter case, the roots attain a much larger size, and are often of two pounds weight.
Although we can scarcely realize that so great a product may be obtained, we nevertheless think that this plant deserves in every respect to be fully tested, and the other circumstances that would recommend the Dioscorea Batatas to the serious attention of every cultivator, are the facility of its culture, and its extraordinary hardihood, which latter enables it, as the experience of the two past winters show, to sustain in open field culture 5° of Fahrenheit, and probably a still more intense degree of cold. Being of a perennial character, the most profitable course would seem to be, to grow crops of two years, as there is by this mode a much greater yield from the increase of size of the tubers.
This plant is growing in various places in the United States. We shall soon have reports respecting it here. Next month we shall give a portrait of the root, and communicate a full account of the mode of culture. - Ed].