Cactus Culture for Amateurs / Being Descriptions of the Various Cactuses Grown in This Country, With Full and Practical Instructions for Their Successful Cultivation

by William Watson

THE GENUS ECHINOCACTUS.

(From echinos, a hedgehog, and Cactus.)

ANY of the plants included in the genus Echinocactus are very similar in habit and stem-characters to the Cereus. Botanists find characters in the seed vessel (ovary) and in the seeds by which the two genera are supposed to be easily separable; but, so far as can be made out by a comparison of their more conspicuous characters, there is very little indeed to enable one to distinguish the two genera from each other when not in flower. A comparison of the figures given in these pages will show that such is the case.

The name Echinocactus was given to E. tenuispinus, which was first introduced into English gardens in 1825. The spiny character of this species is surpassed by that of many of the more recently introduced kinds; still it is sufficient to justify its being compared to a hedgehog. Some of the kinds have spines 4 in. long, broad at the base, and hooked towards the point, the hooks being wonderfully strong, whilst in others the spines are long and needle-like, or short and fine as the prickles on a thistle. The stems vary much in size and form, being globose, or compressed, or ovate, a few only being cylindrical, and attaining a height of from 5 ft. to 10 ft. They are almost always simple—that is, without branches, unless they are compelled to form such by cutting out or injuring the top of the stem; the ridges vary in number from about five to ten times that number, and they are in some species very firm and prominent, in others reduced to mere undulations, whilst in a few, they are separated into numerous little tubercles or mammae. The species are nearly all possessed of spines, which are collected in bundles along the ridges of the stem. Generally, the flowers are about as long as wide, and the ovary is covered with scales or modified sepals. The fruit is succulent, or sometimes dry, and, when ripe, is covered with the persistent calyx scales, often surrounded with wool, and usually bearing upon the top the remains of the withered flower. The position of the flowers is on the young part of the stem, usually being perched in the centre, never on the old part, as in some of the Cereuses. The flowers open only under the influence of bright sunlight, generally closing soon after it leaves them.

The geographical distribution of the species, of which over 200 have been described, extends from Texas and California to Peru and Brazil; they are in greatest abundance in Mexico, whence most of the garden kinds have been introduced. The conditions under which they grow naturally vary considerably in regard to temperature and soil; but they are all found in greatest numbers and most robust health where the soil is gravelly or sandy, and even where there is no proper soil at all, the roots finding nourishment in the clefts or crevices of the rocks. As a rule, the temperature in the lands where they are native is very high during summer, and falls to the other extreme in winter, some of the species being found even where frost and snow are frequent; the majority of them, however, require what we would call stove treatment.

Turning now to a consideration of those kinds known as garden plants, we find that comparatively few of the species known to botanists are represented in English collections, though, perhaps, we may safely say that not one of the kinds known would be considered unworthy of cultivation except by those who despise Cactuses of whatever kind. Their flowers are conspicuous both in size and brilliancy of colour; and in the curious, grotesque, and even beautifully symmetrical shapes of their stems, one finds attractions of no ordinary kind. The stem of E. Visnaga shown at Fig. 48 may be taken as an instance of this—apart from the cluster of star-like, bright yellow flowers seen nestling upon the top of their spine-protected dwelling, the whole suggesting a nest of young birds. This plant is indeed one of the most remarkable of the Echinocactuses, owing to the size and number of its spines—which are 3 in. long, almost as firm as steel, and are used by the Mexicans as toothpicks—and to the gigantic size and great weight of the stem. The following account of a large specimen of this species introduced to Kew in 1845, is taken from an article from the pen of the late Sir Wm. Hooker in the Gardeners' Chronicle of that year. This gigantic plant was presented to the nation, in other words to Kew, by F. Staines, Esq., of San Luis Potosi. Such was its striking appearance, that it was stated that, if exhibited in the Egyptian Hall, Piccadilly, some hundreds of pounds might be realised by it. In a letter from Mr. Staines, here quoted, our readers will perceive how difficult it often is to obtain living specimens of these plants from their native habitats. He writes: "I mean to have a large specimen of E. Visnaga deposited in a strong box, sending the box first to the mountain where the monsters grow, and placing it on the springs of a carriage which I shall despatch for that purpose. My monstrous friend cannot travel any other way, from his stupendous size and immense ponderosity, which cannot be adequately calculated for here, where the largest machine for conveying weights does not exceed sixteen arrobes, or 400lb. This enormous plant will require twenty men at least to place it upon the vehicle, with the aid of such levers as our Indians can invent. It grows in the deep ravines of our loftiest mountains, amongst huge stones; the finest plants are inaccessible to wheeled vehicles, and even on horseback it is difficult to reach them. I shall pack him carefully in mats before applying to his roots the crowbars destined to wrench him from his resting place of unknown centuries. He will have to travel 300 leagues before he reaches Vera Cruz." Being too large to be packed in a box, it was first surrounded with a dense clothing of the Old Man's Beard or Spanish moss (Tillandsia usneoides)—and a better covering could not have been devised—and well corded. Fifteen mats, each as large and as thick as an ordinary doormat, formed the exterior envelope. When unpacked on its arrival at Kew, this monster Cactus was seen as perfect, as green, and as uninjured as if it had been that morning removed from its native rocks, its long, rope-like roots arranged in coils like the cable of a ship. When placed in scales it weighed 713lb., its circumference at 1 ft. from the ground was 4½ ft., and its total height, 8 ft. 7 in.; the number of ridges was forty-four, and on each ridge were fifty bundles of spines, four spines to each bundle. Thus there were 8800 spines or toothpicks, enough for the supply of an army. A still larger specimen was a year or so later successfully brought to Kew, and which weighed 1 ton; but this, as well as the smaller one, survived only a short time. There have been numerous other large specimens of this Cactus in English gardens lately, all of them, however, succumbing to the unfavourable conditions of our climate. Mr. Peacock, of Hammersmith, recently possessed two large plants of E. Visnaga, one of which weighed nearly 5cwt., and measured 8 ft. 6 in. in circumference.

Cultivation.—The soil for Echinocactuses should be similar to that recommended for the Cereuses, as also should be the treatment as regards sunlight and rest. It cannot be too clearly understood that during the period between October and March these plants should be kept perfectly dry at the root, and in a dry house, where the temperature would not fall below 50 deg. There is no occasion for re-potting the Echinocactuses every year, it being by far the safest plan to allow them to remain in the same pots several years, should the soil be fresh and the drainage perfect.

All the larger-stemmed kinds may be kept in health when grown on their own roots; but for some of the smaller species it is a good plan to graft them upon the stem of some of the Cereuses, C. tortuosus or C. colubrinus being recommended for the smaller kinds, and for the larger C. peruvianus, C. gemmatus, or any one the stem of which is robust, and of the right dimensions to bear the species of Echinocactus intended to be grafted. Some growers prefer to graft all the small Echinocactuses upon other kinds, find certainly, when properly grafted, they are safer thus treated than if grown on their own roots. In grafting, the two stems (stock and scion) must be cut so that their edges meet, and in securing them two or three stakes must be placed in such a way as to afford support to the graft and hold it firmly in position.

Propagation.—Besides grafting, cuttings of the stems may be utilised for the multiplication of Echinocactuses, first removing the upper portion of the stem and putting it into soil to root, and afterwards, as lateral stems develop on the old stock, they may be cut away with a sharp knife, and treated in a similar manner. Should a plant become sickly, and look shrivelled and cankered at the base, it is always best to cut away the healthy part of the stem, and induce it to form fresh roots, thus giving it a new lease of life. Seeds of these plants may be obtained from dealers, more especially Continental nurserymen, and to watch the gradual development of the plant from the seedling is both interesting and instructive. The seeds should be sown in soil, and kept moist and warm; in about a month after sowing, the little pea-like, green balls will be seen pushing their way through the thin covering of soil, and gradually but slowly increasing in size, their spines also increasing in number and strength, the ridges forming according to the character of the species, till, finally, they assume the mature characters of the plant, both in stem and habit. The flowers, of course, appear according to the length of time it takes for the species to grow to flowering size.