The Amateur's Greenhouse and Conservatory/Chapter 19
CHAPTER XIX.
GREENHOUSE ROSES.
The rose is not a greenhouse plant, but we shall never tire of seeing roses in the greenhouse and conservatory, provided they are well grown and flower early. If these two conditions are not fulfilled, roses under glass are simply out of place, and the amateur would save worry and vexation by quietly consigning his greenhouse roses to the fire when a general burning of rubbish takes place. A lover of roses will derive one peculiar pleasure from growing them under glass, and that is, he will see them in a remarkably fresh and brilliant condition in the months of April and May, when there are no roses out of doors, and his sheltered pets will be as attractive for the delicate colour and texture of their leaves as for the splendour of their early and most welcome flowers. To do roses well under glass requires a little care, but there is nothing occult in the business, and the amateur who means it, and knows a little of the rose to begin with, will be sure to succeed. A rose house is a fine garden feature, but it is not necessary to devote a structure especially to roses, for they may be grown with either hard-wooded or soft-wooded plants if carefully managed, and, of course, the warmer the house the earlier will they flower. They must have plenty of light and air, and in any case they must be forced gently; so it will be unwise always to put them in heat suddenly, for, instead of flowering nicely, they will become covered with mildew and the flower-buds will drop before they open. In an unheated house pot-roses may be nicely done, provided the aspect is sunny, and the shelter will aid them so much that they will flower a month or more in advance of those in the open ground. The best time to begin is in September or October, when vigorous plants in five- or six-inch pots may be purchased at a cheap rate. These, pruned back to within three or four buds of the base of the shoots, will form nice specimens. They may be purchased either on their own roots, on the brier, or the manetti, according as they are most readily procured; but if there is any choice in the matter, give preference to those on their own roots. Neat standards of one to two feet high, however, are pretty if they have good heads. It is of considerable importance to avoid disturbing the roots of such as are intended for early flowering, and when they come to hand simply stand them in a sheltered position, and cover the pots with leaves or other loose material, to prevent the frost penetrating the soil.
They should be pruned some time in December, and be removed to the greenhouse or pit. If a pit can be devoted to them it should be kept rather close, to encourage them to start into growth early, and on the afternoons of fine bright days a sprinkle overhead with tepid water will be of considerable service. The syringing overhead will be none the less useful if they are placed in the greenhouse, but, of course, it will be necessary to avoid wetting the foliage of such plants as should be kept dry, and also creating a dampness in the atmosphere hurtful to the hard-wooded plants which may happen to be in the house. The soil, even when the plants are quite dormant, should not be allowed to become dust-dry, and when in full growth liberal supplies of water will be necessary. After they are fairly started, moderately weak liquid manure should be employed in preference to clear water. The drainage from the manure-heap diluted with water will form an excellent stimulant; and second in value to that is guano-water, prepared by mixing the guano with clear soft water, at the rate of two ounces to three gallons. Horse-droppings steeped in water also make an excellent liquid manure. It must be used perfectly clear, and the colour should be that of pale ale; if a deeper colour it will be too strong, and will do mischief.
As the growth progresses it will be necessary to tie the shoots neatly, and in such a manner as to ensure well-formed specimens. The only enemies they will have to contend with when making their new growth are green-fly, mildew, and the rose-grub. The destruction of the latter can be accomplished by hand-picking, and a moderate dose of tobacco-water will soon make short work of the green-fly; dusting the foliage with flowers of sulphur is the best remedy for mildew.
When they go out of bloom remove to a sheltered position out of doors, and attend to them with the same care as regards watering as when they were indoors. In a fortnight or three weeks after their removal from the greenhouse, shift into pots one size larger, and use a compost consisting of three parts turfy loam and one part hotbed manure. A few crushed bones mixed with the compost will be of great service in promoting a vigorous growth; and wherever roses are grown in pots, the bones, as they come from the kitchen, should be carefully preserved, and when the roses have their annual shift be broken up and mixed with the compost. A few larger pieces mixed with the crocks will be of service. After they are repotted, stand them upon stones or coal-ashes, and fill in between the pots with dry leaves or other loose material, for the purpose of preventing a too rapid evaporation of moisture from the soil during the hot weather. They must be placed far enough apart to afford ample space for the development of the new growth. During the summer an abundance of moisture will be required, and in the evening, after a hot day they will be benefited by being watered overhead with a watering-can to which a coarse rose has been affixed.
CALCEOLARIA HYSSOPIFOLIA.