The Amateur's Greenhouse and Conservatory/Chapter 16
CHAPTER XVI.
SUCCULENT-LEAVED PLANTS.
In this class are included the cactus, sempervivum, stapelia, mesembryanthemum, and their alliances, the prevailing characteristic being an excessively fleshy texture; in some cases stems and leaves are distinctly produced, in others, the distinction is beyond the ken of the ordinary observer, for the plant appears to consist of a columnar or spherical mass of vegetable pulp beset with formidable spines and bristles. A considerable number of succulent plants deserve to be reckoned amongst the most interesting and useful subjects to which an amateur gardener can give attention, for their variety of form is endless; many of them produce magnificent flowers; not a few are grotesque and comical in outline, and they will all bear occasional neglect with less harm than any other plants in our gardens. Alas! their very virtues are their bane as regards the favours they should enjoy in private gardens, for as they bear neglect with patience, they are ofttimes neglected so much and treated so badly that they cease to attract by their curious seasonal growth and splendour of flowering, and so come to be regarded as worthless, and are, at last, left in dusty windows to perish, or, if they refuse to die, are possibly transported to the rubbish heap.
It is proper, however, to remark that many who profess to collect and cultivate succulent plants, treat them badly through a misconception of their place in nature. The tendency everywhere appears to be in favour of starving these plants, and the fact that they cling to life tenaciously in spite of the worst of treatment appears to justify the system. It is true they can subsist for a great length of time in a state of comparative desiccation at the roots, but it is also true that in their native lands they have the advantage of abundant supplies of water in the growing season, and, as a matter of course, though often located amongst rocks, they are free to send their roots deep and far in search of food. But whatever may be the position of cactuses and their kindred at home, it is certain that all of them that are worth cultivating are worth cultivating well, and the three requisites to success are a rather rich, and substantial, and very gritty soil, abundance of water in the growing season, and the utmost possible amount of light the whole year round. Without exception they should be comparatively dry during winter, and the colder the house the more careful must the cultivator be to prevent injury by damp; but the tender kinds should be rather warm all winter and never quite dry, for when they appear to be quite dormant the flower buds and the next growth are quickly advancing in readiness for rapid development when the stimulus of solar light becomes sufficient. The capability of bearing any amount of sunlight renders these plants admirably adapted for the possessors of those little glass boxes which, in town houses, are called “conservatories,” for, unfit as these structures usually are for plant growing, they answer admirably for sheltering succulent and hard leaved plants of small size on account of their dryness and strong light. The wonderful variety, both of form and colour, that may be ensured in a collection of succulents costing almost nothing in the first instance, and the very small space occupied by them if judiciously selected, are additional reasons in favour of their adoption by amateurs who value a bit of glass more highly than to waste it on ephemeral plants that can only be properly grown in comparatively large and well appointed plant houses.
Echeveria.—This genus comprises some of our most useful decorative plants. E. metallica, E. secunda, and E. secunda glauca are well known as the most useful of the older kinds. E. sanguinea has acquired considerable repute as a bedder, but it makes a charming pot plant, and its deep red foliage presents a remarkable contrast to the others. E. retusa can fairly claim a place with the best spring-flowering plants we have; unlike either of those named above, it has a bushy yet compact habit, and flowers most profusely throughout the spring months. When it is desired to increase the stock of this species, the side-shoots, if taken off" below where the wood has become moderately hard, immediately the plants go out of flower, will quickly strike and make flowering specimens of considerable dimensions by the following spring. E. rosea belongs to the bushy growing section: the leaves average three inches in length and half an inch in width, and towards the end of the summer the margin becomes of a brilliant carmine, which increases in intensity up to the middle of the winter. The tuft of flowers with which each stem is covered in spring is unique, beautiful, and curious.
All the echeverias should be potted in a rather light gritty and rich compost, as they require something more substantial than broken brickbats, which many think is so essential in the cultivation of succulent plants. A very suitable compost may be obtained by well incorporating together four parts turfy loam, one part decayed cow-dung perfectly free from grub, and one part of silver sand.
Very few cultivators are able to increase their stock excepting from offsets, which at its best is a very slow affair. All strike readily from the leaves, and also from seed. A considerable degree of care is necessary in handling the seed, as it is very small, like that of the calceolaria; and if buried too deep and kept either too wet or too dry, a very small proportion, if any, will come up. The soil with which the seed-pots are filled should be very light and sandy, and made perfectly level on the top; then scatter the seed thinly over the surface, and cover it with a sprinkling o£ silversand. A warm greenhouse will be the most suitable position both for the seed-pots and the young plants until they become well established. Leaf propagation is effected by snipping off the small leaves from the flowering stems, and then inserting them in cutting pots prepared in the usual way. It is necessary to insert the base of each leaf in the sand, and to prevent the leaves becoming loose thrust a small piece of stick through them, to fix them firmly in the soil.
Cactus.—Under this head we shall speak of the globular species of the great Cactus family, comprising Mammilaria, Melocactus, Echinocactus, Cactus, and Cereus. To grow them in brick rubbish is a mistake; they require a mixture of equal parts turfy loam and leaf mould, or if the last named material is not available, fibry peat must be mixed with the loam and about a fourth part of the whole bulk of silver sand added. The best time to repot them is from March to May. The operation requires to be carefully performed for two reasons, first, because the plants will suffer if roughly handled on account of their fleshy texture; and secondly, because their terrible spines and bristles inflict painful wounds on hands that approach them rudely. When a cactus is turned out of a pot remove the old soil from the roots and repot firmly, the base of the plant slightly elevated so that the earth will slope down from it all round, and steady it with a few sticks thrust in so as to prevent it toppling over. If you have any difficulty in getting the roots into the pot without crowding them, cut away all the smaller ones and any of the larger roots that appear to be dead or dying. If you can place them on a gentle hot bed at from 75° to 85°, they will make a good start after the potting, and will soon require water, but it is good practice to withhold water until they begin to grow. If well potted they may stand in the same pots three years. It is a great risk to employ manure in the preparing of a compost for the cactus, for although they will take to it and grow freely, they will be likely to rot in the ensuing winter.
Many of the kinds of cactus produce offsets freely, and to make plants of them is the easiest matter in the world. The cylindrical kinds may be cut from in May, and the cuttings should be put in sand in the full sun until they begin to form roots, and should then be potted and have the advantage of a gentle bottom heat. In case of requiring speedy increase of any of the globular kinds that refuse to produce offsets, cut the tip off and lay it on sand in the full sun until rooted. This will form a plant, of course, and then in time a number of offsets will be produced by the decapitated plant. They may be variously grafted on one another, but when the amateur arrives at that stage of practice he will have done with such a humble elementary book as this.
Cotyledon.—A few good plants may be found in this genus as C. velutina, C. coruscans, and C. decussata, for example. They appear to live by their leaves more than their roots, and hence must be extra well drained and potted in a sandy compost. About a sixth part of old mortar of the size of peas may be added with advantage. These plants have acquired increased importance of late owing to the success that has attended their employment as bedding plants associated with sempervivums, echeverias, and sedums, in what is called “carpet bedding;” they are also worth attention as window plants.
COTYLEDON VELUTINA.
Kalosanthes.—For conservatory decoration during July there is nothing to compare with the Kalosanthes, except it be the zonal pelargonium. It is not of course desirable to fill a house with them, to the exclusion of everything else; for they are very stiff and formal in their habit, and the colours are too much alike. But two or three dozen large well-grown plants would be grand for lighting up a house full of ferns and other ornamental foliage plants. To state the case in a few words, they ought to be grown by scores where they can only be numbered by units at present.
The Kalosanthes, or Crassula, as it was formerly called, is by no means difficult to grow well. In the first place, the propagation is effected by taking off the tops of the shoots that have not flowered as soon as the flowers are past: for the wood is then ripe and firm, and not likely to decay, which is the case if the tops are taken off early in the spring, when the plant is in full growth and the shoots soft and sappy. Any light sandy soil will do for filling the pots in which the cuttings are to be inserted, and a layer of dry silver sand should be put on the surface, as it runs down into the hole made for the reception of the cutting, and forms a base for the cutting to rest upon. The cuttings strike with greater freedom this way than they would do if they were surrounded by soil only. After the cuttings are inserted, place the pots in a position where they are exposed to the full light and air, for no close coddling must be attempted, or the cuttings will very soon damp off, especially if the soil is kept too moist. A greenhouse shelf fully exposed to the sun, and a mat thrown over the glass, to break the full force of its rays and prevent them from being burnt up before they have formed roots, are probably the most favorable conditions to ensure their striking quickly. The branches can also be cut up into lengths and struck, if a number of plants are wanted, and the stock of growing points is limited.
After the cuttings are rooted, they must be put into small pots, and there remain during the winter. In the spring, shift into pots two sizes larger, and give them a little encouragement for a few weeks by placing them in a growing temperature, about ten degrees higher than that of the cold greenhouse. Directly the plants begin to make fresh roots into the new soil, nip the points off, and when the pots are full of roots, and the plants require a second shift, they can be either put singly into larger pots, or about three plants potted in one large one. The latter method is preferable, as a large specimen can be obtained quicker, and with less trouble, than by growing them on singly. The plants should now have all the light and air possible, for upon the maturity of the wood depends in a great measure the quantity of bloom the following summer. The drainage of the pots should be perfect, and water applied rather liberally when the plants are growing freely, but sparingly during the time they are at rest through the winter; just sufficient, in fact, to keep the foliage from shrivelling.
From the first the side-shoots must be neatly tied out, to keep them in their places, and prevent their snapping off, which they are very liable to when shifting the plant about. Immediately the beauty of the flowers is gone, cut the plants down in a somewhat similar manner to that in which pelargoniums are usually cut back after flowering. Give a little extra warmth to induce them to break quickly, and when the young shoots are about an inch in length take the plants out of the pots, remove a portion of the old soil, and repot in a clean pot the same size as that from which it was taken. No exact rule can be laid down as to how low each shoot should be pruned, but they should be cut back to where the wood is firm, and a certain uniformity preserved. Fibrous loam, mixed with a good proportion of leaf-mould and sand and a liberal sprinkling of broken crocks, forms the most suitable compost.
Klenia.—These are of small importance, yet two sorts at least ought to be grown, and these should be K. repens and K. tomentosa. The first has leaves of a light metallic blue colour.
Pachtphiton.—The beautiful silvery-leaved P. bracteosum has now become so well known that it is scarcely necessary to say that its distinct character and unique appearance render it well entitled to a place in the most limited collection. P. lingua is very similar in growth to the preceding, but the leaves are dark green instead of white. Large specimens of bracteosum are valuable for associating with Echeveria metallica in the flower garden, as well as in pots in the greenhouse or conservatory.
Rochea.—The beautiful R. falcata ought to be grown extensively for conservatory decoration during the autumn, instead of being grown merely as a curiosity. Even where soft-wooded plants generally are cultivated, a dozen or so of this Rochea should find a place as much for the showy appearance of the flowers as for the distinct and somewhat singular character of the plants. The Rocheas grow freely in the soil advised for the Echeverias, and are increased by means of the side-shoots formed at the base.
Sedum.—A large number of the hardy dwarf-growing species are well worthy of a place under glass, the best and most distinct being S. glaucum, S. multiceps, S. pulchellum, S. atro-purureum, S. sempervivoides, S. kamtschaticum, and S. hispanicum. The above should all be grown in rather deep pans, filled with a light and gritty compost. The soil should be raised about three inches higher in the centre than at the sides, which can be easily accomplished by fixing a few pieces of stone in the middle of the pans, and then dibbling in the young shoots over the entire surface.
Sedum Sieboldi and S. spectabile (syn. Fabarium) and their variegated varieties require a distinct system of management from the preceding, and are most valuable for conservatory decoration in the autumn. The first makes a capital basket plant, and the second should be trained in exactly the same way as specimen pelargoniums are trained. Very little training will, however, be required, beyond simply tying out the young growth as soon as there is the slightest prospect of the plants becoming unshapely. The culture of both species is
SEDUM SIEBOLDI.
the same, excepting that the former should be grown under glass and in baskets, instead of in pots and in the open air during the summer.
To propagate a fresh stock, take cuttings of the new growth in February, March, April, and May. Prepare them as cuttings by removing the leaves from the lowest joint, and dibbling them firmly into sand. If made early, a gentle bottom-heat will be required, but after March the cuttings will strike without heat. The first season of growth from the cutting-pans keep the plants in three-inch pots, and allow them to grow as they please. They may be put out of doors till the end of September, and must then be housed. The next spring shift the stock of Sieboldi into pots one size larger, and that of Spectabile into two sizes larger, and in these sizes they will flower nicely. The flower-buds appear some time in advance of the flowers, but when at last these open, in the month of September, their lively rosy pink hue and symmetrical disposition are remarkably beautiful, and contrast chastely and cheerfully with the peculiar tint of the leafage. After the blooms have faded the stems die down, and are immediately succeeded by a new growth from the root, and thus, if encouraged by good culture, a specimen of either species will become larger and larger every year, and may be grown ultimately to colossal dimensions. Both require a rich light soil, and the best compost for specimens is as follows. Turfy loam two parts, rotten dung one part, bricks broken to the size of hazel nuts one part, sharp sand one part. In this mixture they should be potted firmly, and in spring, when the new growth is beginning to advance, the plants should be shaken out, a considerable portion of the soil removed from the roots, and be repotted in pots one or two sizes larger than the last. They require to be always exposed to the full daylight without shading at any season, to have abundance of water from April to August, and at other times to be kept merely moist enough to prevent flagging. When too large the roots may be divided.
Sempertitum.—These must have a prominent place in a small collection of succulents, because of their bold and distinct characteristics. The best of the large-growing species are S. glutinosum, S. cuneatum, S. canescens, T. canariensis, S. S. arboreum, S. arboreum atro-purpureum, a fine variety with deep bronzy leaves, S. palma, a noble kind with a table-like head supported on a thick stem about two inches in diameter, and S. tabulaforme with its table-like top supported on a stout stem varying in height according to age, instead of resting on the top of the pot. S. bracteosum is distinct from all the other kinds, and one of the freest growers in the whole family, as a huge specimen two or three feet in height and as much in diameter can be grown in a very short time. It is one of the best window plants in existence, as it will grow freely in the most unfavorable quarters. The cuttings are most easy to strike, and after they are potted off singly will soon form fine specimens without any stopping or training. They are by no means particular as to what they are potted in, but the most suitable compost is one consisting of turfy loam, leaf-mould, and silver sand in equal parts. The amateur who has no partiality for succulent plants may safely adopt the purple leaved variety of Sempervivum arboreum, for it is one of the noblest greenhouse plants in cultivation, and with very little care will in a few years grow to the stature of a man and produce pyramids of yellow flowers in the early spring. To be safe from frost is enough for it all the winter, and to be out of doors in the full sun all the summer will contribute to its welfare.
Stapelia.—This genus produces exquisitely beautiful flowers which are elaborately pencilled, but have no other attractions, and emit the unpleasant odour of tainted meat. A sandy soil must be provided for them, and a warm position all the winter.
BRACHYSTELMA BARBERIÆ.