The pruning of the different species varies according to the habit of growth and the purpose for which they are used.
The Pillar Roses (those that are used in covering stumps of old trees, trellises, etc.) which are generally strong growers (under fair conditions, making an annual growth of from six to twenty feet) must be treated differently in the way of priming from those which are naturally of a bushy, dwarf habit. The Climber is grown for the purpose of covering large areas and to give great showers of bloom, whereas the dwarf kinds are grown mostly for their fine form or size, individually, or in clusters of from three to six in a cluster. In pruning the Climbers, in December or January, all that is necessary is to thin the shoots of any weak or worn out or dead or surplus branches and shorten the previous year's shoots by cutting off the soft or unripened tips, on the other hand being careful not to thin too freely thus exposing too much of the wall or trellises on which they are trained.
The Hybrid Perpetuals, the Bourbons and the tea-scented sections which are grown in beds or borders and are desired for their individual flowers, should be pruned back in December or January each year, leaving only from four to eight buds on each shoot of the previous year's growth.
When the bushes are four or five years old, it will become necessary to thin out some of the old stems, but only enough to keep the middle of the bush from becoming crowded too much; this admits light and air to each growth and encourages stronger stems and finer flowers.
Should, as is very often the case, the plants show a tendency to make weak, spindly growth, it is a good plan to take them up in early Spring and either transplant them into new soil or trench the ground over (enriching it with a plentiful supply of old manure) and replant them after cutting them well back and trimming in the roots, pruning off any which are dead or diseased.
The Rose is subject to several diseases, the worst of which is Mildew; this should be attended to at once and not left until all the leaves are attacked, but, as soon as the first speck of Mildew is observed, the whole of the plant should be sprinkled with a dusting of flowers of sulphur. The Rose-rust is another disease which frequently attacks the leaves; it forms on the underside of the leaves in red dots or small masses. As yet no cure has been found for this disease, so as soon as a leaf is found with this rust upon it, it should be picked off and not merely left on the ground but should be burned up to prevent the disease from spreading to other plants.
The Rose is also attacked by several species of Aphides, commonly called green or brown fly. These should be got rid of by syringing with strong soap-suds in the evening and washing off in the morning with the hose; this operation should be continued each evening until the fly is all cleaned off. A solution of tobacco water is also effective, and sometimes dusting the leaves with tobacco dust will have the desired effect.
When caterpillars infest the leaves, they generally coil themselves in the folds of the leaves. Press the affected leaves firmly between the finger and the thumb, thus killing the caterpillar, or the leaves can be picked off and burned.