There are two ways of increasing roses: by means of cuttings and budding. With cuttings,, some years pass before a mature rose bush is obtained. Although it is applicable to ramblers and many of the vigorous flori-bundas of the Poulsen type, it is a difficult method to adopt for hybrid teas. Usually far more vigorous roses are obtained by budding than from growing cuttings.
Taking Cuttings
It is important to choose well-ripened shoots. As a rule the soft pithy wood does not readily root. The cuttings should be taken in August or early September and be about one foot long and a little over a quarter-inch in diameter. They are cut horizontally just below an eye, while at the top the cut should slope downwards from above the bud. The lower leaves from those eyes likely to be below the ground are removed. At the same time, to avoid the growth of suckers, the lower eyes should be eliminated by a wedge-shaped cut with a sharp knife.
The cuttings are inserted in about two inches of sand at the bottom of a wedge-shaped trench about nine inches deep. Before doing this the lower ends of the cuttings should be wetted and dipped into a hormone rooting-powder to encourage root formation. The cuttings should be planted about six inches apart. The trench should then be filled with soil and gently trodden in so that cuttings are vertical. After planting they should be well watered. They are left in this position until the following autumn, when they may be transplanted.
Budding
Almost all the roses grown are propagated by budding. The underlying reason for this is that seedlings grown on their own roots are rather weak specimens that seldom survive the winter. If the latter was the only method of propagation, there would be very few roses today. Undoubtedly the surest method of multiplication is budding. In addition to this reason the pedigree of our present-day roses is so very complicated that it is impossible to reproduce a variety from its seeds.
Budding consists of uniting live cell tissue of the rose to be reproduced with that of a related rose plant which is so well-developed that it has a good root system. This is known as a rootstock or understock. The stocks used for this purpose are always members of the rose family, but the actual variety chosen depends much on climatic and soil conditions. The most popular understock in England is R. canina (dog rose or briar) seedling. Unfortunately it may vary in quality, and there are a number of sub-varieties, cuttings of which are irregular in growth and take. Moreover such types of briar have a tendency to produce suckers. One sub-species of R. canina, R. laxa, is extremely uniform and does not produce suckers. R. canina rootstocks are the best for heavy and average soils, while those of R. multiflora (or polyantha simplex) give better results on poor sandy soil.
Any of these species can be effectively used for bush roses. For standards, it is more usual to employ R. rugosa. In the following spring, they ought to be rooted sufficiently to allow transference to nursery beds, where they are planted ten inches apart in rows about two feet six inches apart. When planting R. canina, it is advisable to use hormone powder to accelerate rooting. Alternatively it is possible to buy understocks. It is claimed by some budders that roses grown on seedling stocks live longer than those on cutting stocks. The seedlings are planted in March in a bed which is not to be their final resting place because it is better to transplant first-year roses (maidens) after they have flowered in the year following the budding. This enables the roots to be trimmed, removing any deep taproots and so encouraging the growth of the all-important surface roots.
Such seedling rootstocks are planted so that the neck, I.e. the portion of the stalk between where the roots fork and the lowest green shoots, is about an inch or so out of the ground.
Final stages in preparing a bud for budding
Rooted cuttings are put in as shallow as possible. For con-venience when budding, rootstocks should be planted so that they are sloping towards the spot where the budder will ultimately work.