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.
Rhubarb, or, as it is often named, Pie Plant, is composed of a number of varieties that have emanated from two species of the genus Rheum, viz: R. rha-ponticum and R. undulatum, each of which in a natural state is very distinct in external appearance. The former has furnished most of the green and more cylindrical-stalked sorts, and all the tardy ones; while the latter gives us the semi-cylindrical, red, and earliest kinds. Cross breeding, however, has been now carried out so far, that the true specific difference is nearly obliterated, and the result is a great improvement in size, productiveness, and flavor. So much has righly directed skill accomplished in this case, that a drastic acid leaf, not much larger than a yellow dock (to which these plants are nearly allied) has now attained to the dimensions of four feet in diameter under the best of culture, and a greatly superior sprightly acid taste in the three feet long and correspondingly thick leafstalk, the only part used for culinary purposes.
Some authorities say that a third species, R. hebridum, has served a part of duty in this general amalgamation; but, as the name indicates, we doubt if this is, or ever was, anything more than a natural bastard; others, again, assert that R. palmatum furnishes the officinal rhubarb root, while the fact is, it has not yet been accurately determined which is the true and genuine article. Likely enough many sorts are manufactured into what should be from one source only, and that the greater part of the difference in medical action arises from this cause. These medicinal properties are purgative, tonic, and yet astringent, and there is little doubt but we get all the three in a modified form from the parts used in cookery, which makes it self-evident that we could not use a better alterative, in a reasonable quantity, as food at the time of change from the extreme winter's cold to summer's heat; the season when rhubarb is in greatest abundance.
The genus Rheum, collectively and aboriginally, inhabits the wastes of Siberia, the plains of Tartary, and the lofty mountains that cut off India from the cold table land to the north; and in cultivation it delights in a cool, moist, but well-drained situation. As an edible, it is invariably improved by high culture, and is best suited in an open, light, deep, rich soil, having a porous under base, through which the superfluous water may pass away. Nothing will be gained by stinting this plant; consequently, if we wish for profit, we must trench deep and manure heavily. For a general and permanent crop, proceed as follows: Early in the fall choose a situation and soil as near to the above described as the limit of the place will admit of; the exact circumstances matter little, and mark off the size of the intended required space. This for a large family may be about thirty square yards, and will accommodate as many plants. Commence at one end, take out a trench two feet deep, by two feet wide, wheel the soil to the opposite end, have in readiness a good quantity of rotted barn-yard manure, cover the bottom three inches thick, and over this a portion of soil from the next excavation that is to be, mixing a portion of each as the work proceeds, so that when the next trench is opened a like two feet, the first shall have received six inches in depth of the manure.
At the end of two or three weeks turn over the bulk, mix again, and level down. We are now ready for planting. Mark off distances of three feet square, and place one plant in each, so that the upper part may be elevated some three inches above the general level, spread out the rootlets carefully, and cover from the sides, leaving a small mound sloping upward towards, and two inches above the crown. Spread over the whole surface two inches of rotted manure, and all will be right for the winter. The best roots for planting are those which have been separated into single buds the season previously; but when such are not to be had, the large stools may be divided into such, retaining a quantity of healthy roots to each. A planting thus made will continue productive and furnish excellent quality for five or six years, if an annual mulching and forking be practised. It is also advisable to cut out the flower-stalks immediately as they are discernible, as if left to produce seed they exhaust the roots considerably.
When there is an ambition for developing this plant to its greatest capacity, it is requisite to make a plantation every year, that of the present doing duty for the next For this purpose, in the early part of summer, prepare, as. before stated, so as to be ready for planting the latter part of June. At this time examine your old roots; choose those which have good crowns ; take up carefully; remove all but the youngest unexpanded leaves; divide each offset, and retain all the roots possible. Plant and mulch as before advised. If the weather is, and should continue to be dry, keep the ground moist by copious watering. By this process the active circulation is retarded during the summer months, and the after centralization, which produces the flower stems in embryo, prevented; and there is time enough through the autumn to furnish a solid leaf-forming bud with abundance of roots that will absorb any amount of liquid manure, if not applied too strong, when the leaves are somewhat expanded the next spring. At this time put on an extra mulching, and every week or ten days give a thorough soaking with the liquid drainings of the dunghill or hog-pen; this latter should be weakened by an equal quantity of water, and both should not be in too fresh a state.
Guano diluted, one pound to twelve gallons, and freely used, will answer almost equally well. If there is good drainage below, the ground may be saturated with these substances ; but care should be exereised in the application, as the central crown would be rotted by frequent contact.
It will be seen from a careful perusal of what is here written that there is a previous preparation of the plant before these powerful stimulants, so plentifully supplied, are recommended, and that its physical condition is ready to receive them. Under any other circumstances they would do more harm than good. Never apply such things to any plant unless it be healthy at the roots, and in active growth. By this process I have grown rhubarb stalks three feet long, and seven inches in circumference, the leaves being four feet in diameter; and others have done, and still may do better with the right sorts.