Suckers
Suckers are sometimes produced by Roses, and may be utilised for increasing stock, if desired. They should be taken off in autumn, and planted out separately; if there are no roots, some will generally form if the suckers are inserted rather deeply in sandy soil, and nursed a little through winter. Sports. Several varieties have originated from sports that have been observed on Roses, as well as on many other plants, and which arise from some cause which seems to affect the colour more than any other quality. Sports cannot be artificially produced; all that can be done is to perpetuate any which appear, and are worthy of it, by one of the ordinary methods of propagation. Division. Propagating Roses by division is not much practised, but it may be adopted with such as the Fairy Rose (R. indica minima), the Scotch Rose (R. spinosissima), and a few others, which spread and grow, as it were, into bushes.
Budding. This is the principal mode of propagating Roses, and the operation is one which may be successfully carried out at the proper season, after a little practice, by almost anyone. Nurserymen who make Roses a speciality have thousands budded annually. Various' stocks are used, that most extensively employed being, perhaps, the common Dog Rose of the hedgerows. Stocks obtained from the seed of this plant are also much favoured, in some establishments, for dwarf Roses, particularly Teas. The Manetti is also largely employed. For effecting a union, it is necessary that the stock be in a growing state, sufficiently so to allow of its bark separating freely from the wood beneath. The buds should be dormant, well matured, and preferably obtained from firm shoots that have borne flowers; sappy wood shoots are unsuitable. The latter part of June, and all through July, is the principal season for Rose-budding outside, as the stocks are then in a growing state, and plenty of buds are generally obtainable. Under glass, and with the stocks established in pots, it may be carried out extensively earlier in the season; according as buds can be obtained, the stocks may be introduced into a slight warmth, and soon brought into proper condition. On the process of preparing and inserting buds, full information may be found under Budding, where also further remarks are made on the various stocks that are used for Roses.
Grafting. This is an effectual mode of Rose propagation; the whip or splice method and crown-grafting are best suited, but the parts rarely unite so well as they do when budded. Cleft and saddle-grafting are also practicable. Stocks may be of the same sorts as those used for budding. The work is performed principally in January and February under glass, and in the open air during March. When the stocks are in pots, they may be started in a little heat, and so got in advance of the scions, which may be procured in about a fortnight afterwards from well-ripened, dormant trees outside. After the grafts are inserted, the stocks should be returned to the same heat as that in which they have been growing, until a union between the parts has taken place, when they may be gradually hardened off and grown in cooler and more suitable quarters. For description of the methods of grafting above named, see Grafting. CULTIVATION. To grow Roses successfully, a rich soil must be provided, such as a deep loam of a stiff rather than light nature, although the plants on their own roots will thrive better in rather light soils than will others worked on the common tall Briar or on seedling Briar stocks. The wild Rose grows naturally in heavy, clay land; under cultivation, it is, consequently, best suited with strong soil of a rich nature. Shallow, sandy or gravelly soils are unsuited for Roses, and so, on the other hand, are any which are improperly drained. In gardens where Rose-beds have to be formed in unfavourable situations, it is best to dig out the natural soil in the first place, and replace it with a properly-prepared compost; or it may be that changing a portion will suffice. A depth of about 1 1/2ft. should be provided for such strong-growing kinds as most of the Hybrid Perpetuals, and a similar depth is advised for all Roses if it can be provided. The soil can scarcely be made too rich; plenty of manure may be added when the ground is being prepared for planting, and an annual top-dressing in addition is generally found beneficial, and indeed necessary, in the production of good flowers. It may be applied with advantage soon after growth commences, in spring; the flowering shoots are then pushing up, and need plenty of feeding from the root. Respecting situations, there are few in which some representative of this beautiful genus may not be grown successfully. It is not convenient, nor, perhaps, desirable, to attempt the formation of a Rose-garden in all gardens, even when they are extensive; but beds of Roses may generally be introduced into flower-gardens and pleasure-grounds, and any quantity of plants, so far as circumstances and space admit, may be put into other positions without any fear being entertained of having too many. For cutting purposes, in private establishments, it is found a good plan to devote a portion of the kitchen garden to Rose-growing, where the ground can be well trenched previous to planting, and enriched with manure at any time when it is considered necessary. For a Rose-garden, an open situation is desirable, with a south or south-eastern aspect, and sheltered from other points, particularly north and east. Climbing Roses are very beautiful, and generally very floriferous; they may be employed with good effect for covering arches, arbours, pillars, &c., and also for training up trees and tall-growing shrubs. Transplanting of all the more hardy Roses may best be done in October and November. Tea varieties, and any others of a tender nature, are generally not safe to withstand the winter unprotected, and are consequently planted in spring. Dwarf plants should be allowed a space of from 2ft. to 3ft. clear between them, standards not less than 3ft. Sometimes, both are planted alternately in beds. Roses are better arranged by themselves in this way than intermixed with other plants; and this remark also applies to the flowers when cut. It is so customary to find Roses mixed with well-night everything in the way of cut flowers that few persons keep them exclusively by themselves; but it is only by doing so that their full beauty as cut flowers may be seen. The foliage, too, that belongs to plants from which the flowers have been cut seems to suit each so well individually that some of it should always be used; the foliage, for instance, from Tea Roses does not look well with Hybrid Perpetuals, that of neither sort of leaves will do for mixing with flowers from any of the species, and so forth.
The pruning of different Roses depends a good deal on the class to which they belong, the way in which they are trained, &c. Autumn and spring pruning are practised, the latter most extensively, especially since the springs of late years have been so precarious. If a shoot is shortened back in autumn, the eyes that are left, with the intention of their remaining dormant until the following spring, will often be excited into growth during winter, because of the prevalence of mild weather; they then succumb to the first frost. Spring pruning may generally be performed from the middle to the end of March; but the season varies according to the weather and the state of the trees. The young shoots will frequently grow out several inches at the top; and although this growth will have to be sacrificed, it would be unsafe to prune, unless the season were sufficiently advanced to insure the development of the eyes that are left, without injury from frost. Standard Hybrid Perpetuals have to be cut rather severely to keep their heads within limits. All small shoots should be kept removed, and the strongest ones allowed plenty of space. Dwarf plants of this class may be allowed to grow more freely; but the shoots must be kept thinned, in order that they may become thoroughly ripened. Badly-ripened wood never bears good flowers; it should, therefore, in pruning, be removed first, and afterwards other shoots which are misplaced or tend to cross each other and destroy the form and symmetry of the trees. Hybrid Perpetuals may be cut back to from four to eight eyes, according to their vigour and habit. Teas, in the open air, with a few exceptions, seldom grow very vigorously, and a thinning and slight shortening of the shoots are often all they need. Hardy Pillar and Climbing Roses, such as varieties of R. sempervirens, may have their lateral growths shortened back after flowering; this admits light and air to the others left, and but little further pruning will be necessary in spring. If more vigorous shoots are required than those which develop, hard pruning to two or three eyes will cause their production. The amount of pruning which Roses need, and the time and manner of performing the operation, are subjects very widely discussed, and upon which much difference of opinion exists. The principal conditions are: judgment on the part of the operator, a knowledge of the varied habits of Roses, and treatment of each individually as its requirements suggest.
Roses in Pots and under Glass. Greenhouses and conservatories without Roses are rarely found, as, fortunately, no one with a cool glass house need be afraid of inserting a plant to cover the back wall or a portion of the roof, if pot culture cannot be attempted. The Teas are especially well suited for pots, and also the Hybrid Perpetuals; with a sufficient quantity of plants, and by forcing and management, flowers may be obtained nearly or quite the whole year through. Plants for pot culture are best on their own roots--that is, raised from cuttings or layers--but others worked on Manetti stocks or seedling Briars are available. They may be grown from the first in pots, or lifted from the open ground, in September or October, and potted. A rich compost of turfy loam should be provided, with some decayed manure, charcoal, and, if convenient, a few 1/2in. crushed bones intermixed. If the plants are intended for forcing, they should be established in pots at least for a season; the flowers seldom develop properly on those lifted only a short time from the open ground. The Hybrid Perpetuals may be plunged outside during winter, or until required for forcing, and protected with dry litter or bracken; the Teas should be placed for safety in a cool house or pit. As the growth allowed in pots must be somewhat limited, close pruning will be necessary, particularly in the early stages of training, and the shoots must always be kept well thinned by summer disbudding. Established plants do not need repotting every year; if their roots are healthy and not pot-bound, a top-dressing of rich soil sometimes answers better than potting, and liquid manure may be given when the flowers are developing. For forcing Roses to flower in early spring, artificial heat is necessary, and the plants should have been grown some time previously in pots, as already noted. After being pruned and otherwise prepared, a portion may be introduced into a little heat during December, or early in January. About 50 deg. at first will suffice, but when growth commences, and the days lengthen, this may gradually be raised to about 65 deg., with plenty of air on all favourable occasions. Syringing may be practised daily until the flowers begin to expand, when the plants may be transferred to a cool greenhouse, unless they are only required for providing cut flowers, when they should be subjected to a cool temperature and plenty of air. After flowering, the plants may be placed in a sunny position outside until the autumn, but they must not be neglected in watering; the proper maturation of the wood for the succeeding year must be one of the main objects in view.
Other methods of growing Roses have to be adopted when the plants are trained to a greenhouse roof or rafter. For this purpose, they are best planted in a prepared border, which may usually be made inside the house; good soil and drainage must be provided here, as in other situations. Nurserymen supply pot plants specially grown with long shoots for training; or the growths may be easily trained up, if a light, suitable position can be provided, which, however, is not always convenient when stages and hot-water pipes come in the way. Roses permanently planted under glass must be allowed their full season of rest all the winter; their roots should then be kept moderately dry, but almost any quantity of water may be given during the summer. Thinning of the numerous flowerless shoots which appear must be constantly attended to in the growing season. This will admit light and air, and prevent the necessity of removing the large quantity of wood at pruning time that would otherwise be necessary. Many climbing varieties of Tea Roses are unsurpassed amongst greenhouse climbers during spring and summer.
FUNGI. Several species of Fungi, belonging to widely different groups, are parasitic upon the living leaves and young branches of cultivated Roses, and many others are found growing upon dead and withered parts of the plants. The latter do not need further mention, though possibly some of them may be injurious, in their younger stages, to living parts of the Rose-plants. The most generally hurtful of all the true parasitic Fungi is Rose Blight, which is one of the so-called Mildews, and belongs to the group of Erysipheae (see Mildew and Oidium). Its scientific name is Sphaerotheca pannosa, but it differs generically from Erysiphe in little save that in each of the minute, black perithecia scattered over the mycelium there is only one ascus. In this lie eight oval spores. S. pannosa grows on all young parts of plants in the form of a dense, pale grey, velvety coat, covering large patches of the surface. The parts attacked by it are much altered in appearance, the leaves becoming blistered and twisted, and the flower-stalks and calyces swollen and distorted. An account of the structure of the Fungi in this family will be found under the headings quoted above. S. pannosa is found to grow also on the Peach. The application of powdered sulphur, or of weak solution of sulphide of potassium, will destroy the Fungus without injury to the host-plant. Another kind of Mildew has been observed on the lower surface of the leaves of Roses in conservatories. This also forms grey patches, but they are less extensive and far less dense than in the former species. Irregular, brownish spots appear on the upper surface of the leaves; they extend over the leaves, which soon wither. These are the work of Peronospora sparsa, and bear scattered conidiophores, or slender, branched stalks, on which oval conidia are produced, on the tips of the branches. No remedy is known for this Fungus; and all parts that bear it should be cut off and destroyed. See Peronospora.