This section is from the book "The Gardener V3", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Many are apt to overlook and neglect both Roses in pots and those that are planted permanently in the Rose-house during the season when they can be gathered in abundance outside. I have seen Roses in pots that have done duty and bloomed, much neglected even when the thought that outside Roses would be an uncertainty, or a fear entertained by the majority that outsiders would be severely injured, if not killed outright. Even when this state of things has been uppermost in the minds of those most interested, Rose plants after blooming have been carelessly treated and cast aside - either forgotten or left to chance until wanted for forcing again, and have then proved almost if not quite a failure. One would naturally think, when the outside supply is likely to be somewhat limited, that greater care would have been bestowed upon those in pots, which, if properly treated, would have made a supply certain. There are those who have Rose-houses and require them for early work, but keep them slowly moving for the few flowers they produce; and then, instead of treating them properly, to force upon them a good rest, are what they call partially pruned back and allowed to go on again. These, as I have before stated, soon become a prey to mildew, and look unsightly.
This system will not grow Roses long, and in the end (to say nothing of the annoyance it causes those who cultivate them) will prove not only more laborious than wise and judicious treatment, but will also lessen the chances of producing creditable blooms. The Rose-house that has to produce Roses from the New Year onwards must now be in the autumn of its growth, to be followed shortly with as complete a rest as it is possible to force upon Tea kinds grown under glass. They have a great inclination to continue to grow, whatever system may be followed to bring them completely to rest. This can only be accomplished by giving full ventilation day and night, with the doors standing wide open. The atmosphere should be kept dry, as well as the soil about their roots; but not overdone, or injury to the roots will be the result, as Roses should not suffer for want of water during any season of their growth. The cold nights towards the end of September, when full air is left on, act wonderfully in bringing them completely to rest - an essential point in their cultivation.
The flower-buds in the Rose-house should be removed as soon as they appear after the beginning or middle of July. By allowing blooms to grow and develop until pruning-time, the plants are considerably injured for the following season. Opinions appear to differ on this point, and some contend that the production of blooms does not exhaust or impede growth. I am, however, convinced that it does, and more especially with such varieties as are suitable for the bed in the Rose-house proper, being continuous bloomers, and differing much in this respect from such kinds as Gloire de Dijon, that flower profusely in the early season, and then devote the remainder of the season to growth and recruiting themselves; and during the growing period only produce, comparatively speaking, a few solitary blooms. The mistake that often arises in gathering blooms from the Rose-house until a late date is a lack of forethought, when the outside supply is growing scarce. A good number should be grown in pots for an autumn supply. La France for this purpose is really a gem, and, like many Tea kinds, continues to bloom as long as required. I have some plants at the present time that have been flowering over six months, and would doubtless, if allowed, go on for three or four months longer.
Some of the varieties of Bennett's Hybrid Teas will, from my experience, prove valuable for pot-culture, although I do not think any of them can compare for usefulness in every respect to that beautiful variety just referred to. A box of blooms in the exhibition tent scarcely appears complete without a bloom of La France, which is always conspicuous. It is questionable if ever Bennett's varieties become so popular in this respect, and will by many be condemned as useless. Cultivators generally are very liable to rush to hasty conclusions at the non-appearance of kinds in the exhibition tent, and upon these grounds exclude them as poor and worthless. Their merits as exhibition blooms are not sufficient to indicate their usefulness. What would exhibitors of Rose-blooms say to Safrano, Isabella Sprunt, or the old China Roses 1 yet they are all lovely in the bud, and their adaptability for flowering profusely in the winter secures for them a foremost place. On the same standard should the Hybrid Teas be judged, and amongst them Nancy Lee should hold a prominent position. It grows well on its own roots, strikes as freely as the La France, and blooms when quite small, continuing to do so for a long time.
Vicomtesse Falmouth is also useful, flowering well in a small state, and is well adapted for decoration in 5-inch pots : it grows strong enough for this purpose on its own roots. Hon. Geo. Bancroft is useful for the same purpose. Beauty of Stapleford is a stronger grower than the preceding two, and a most abundant bloomer. Duchess of Con-naught and Pearl are also very good and useful. The two first named, so far, have distinguished themselves best with me.
To return to the Rose-house, in which, at this season of the year, we allow the growths to ramble at will for the sake of looking tidy and neat, growers generally tie them closely to the trellis. This should not be done in the latter stages of growth, as by so doing the shoots that have been previously made are induced to break again and form wood which will neither be of service nor ripen, thus prolonging the growing season of the plants. Our plants are tied down for the sake of appearance, while the family is here for a short time in July, which is not sufficiently long to cause them to break; the ties are then cut and the shoots set at liberty. By allowing them an upright growth soft wood is prevented in autumn, and light and air play more freely amongst the shoots. By the end of the present month, or early in September, if growth shows signs of ceasing, we remove all the soft-growing ends, which further induces them to rest. Care must be exercised in this direction, and the grower must be perfectly satisfied that they will not again break into growth. This year our bed of Roses has grown remarkably strong and bloomed abundantly.
Through the severe weather in winter they did not fail to give us a good supply of buds, especially from Safrano and Isabella Sprunt. The scarlet variety of the former is very free, and will no doubt prove invaluable, but we cannot yet say how it will stand mid-winter forcing. Our Rose-bed will be pruned early in October; and in doing this operation a good many weak shoots are removed and the strong ones well shortened back. Hitherto they have been pruned rather hard back, and the result has been very satisfactory. After pruning, the house should be thoroughly cleaned, and a small portion of the top soil of the bed removed, replacing it with good rich loam, a quantity of small bones, and wood-ashes.
Roses in pots for the autumn supply should now be growing freely, plunged outside. They should be liberally supplied with manure-water to keep them growing, removing the buds as they appear until the end of the month. After this they can be allowed to form, and should be taken indoors before being checked with the cold. They should occupy a position not far from the glass, where a temperature of 50° to 55° at night can be maintained. If properly managed, these plants will produce a good quantity of bloom from the end of October until Christmas. The China J loses can be placed for a time either in cold frames or in a house, and introduced into heat a little later in the season.
Hybrid Perpetuals in pots will also require attention at once. If properly treated after flowering by hardening off and plunging outside, well watered, and the foliage kept clean by means of syringing up to this date, the earliest batch will be ready for potting - in fact, all but the latest batches can be gone through. As a rule, we turn all out to see if the drainage is right; and if potting is not needed, they are top-dressed with some rich compost. The majority require potting either into larger pots, or by considerably reducing the old bulb with as little injury to the roots as possible, placing them again in pots of the same size, with a good quantity of new compost. When potting is done early, while the foliage is fresh and good, large quantities of roots are afterwards formed, and the plants become well established again before pruning-time arrives - the roots frequently abounding in -quantity round the sides of the pots when attended to in due time.