Pruning established roses
When? In the spring for most classes (exceptions later) when new shoots are about 1/4 inch long. The questioning beginner may ask, "Do not these shoots use food materials stored in roots and stems, which is lost when they are cut off?" The answer is "Yes," but Roses start to grow too early for their own good, and the new shoots are sometimes killed by late frosts. If they are pruned before growth starts, the lower buds are forced to grow, and if these are killed, there are few or none to take their place.
This is a common occurrence, which usually can be attributed to winter injury undiscerned at the time of pruning. If you live in the North, when you have cut off dead and injured wood, your pruning will be finished, so far as the varieties (Tea and Hybrid Tea) least resistant to severe freezing are concerned. When there is a lot of top growth left after dead wood has been removed, further procedures are regulated by the class to which the rose belongs and the purpose in view.
When shortening canes, make the cut just above a bud pointing in the direction you wish to have the shoot grow. Usually an outward-pointing bud is chosen to avoid crossing branches. The cut should be about 1/4 inch above the bud and slope slightly away from it. When removing old, worn-out branches from near the base, cut as close as possible to the parent branch.
Tea and Hybrid Tea
First take a good look at the bush. If there are branches which are rough and gnarled and carry none but thin weak twigs, cut them off close to the parent branch. Except when dealing with old neglected bushes, there may be only one or two of these, or maybe none. Then cut off any thin, weak shoots and cut back the strong remaining shoots one third of their length if your objective is many flowers; one half to two thirds if you prefer large but fewer flowers.
Climbing Hybrid Tea
These are vigorous sports of the bush-type Hybrid Tea Roses. Pruning should be kept to a minimum. All that is necessary is to cut out dead and worn-out shoots and to shorten or remove weak, twiggy shoots.
Dwarf Polyantha and Floribunda
Ordinarily these need but little pruning beyond cutting back, lightly, the shoots that have bloomed and occasionally removing near the ground line some of the oldest and least vigorous branches. There are some who practice cutting back the Small-flowered Polyanthas almost to the ground every year when they wish to keep them within a certain height.
There are two distinct methods of handling this group. One is to treat them essentially in the same way as Hybrid Teas, except that because of their usually more vigorous growth they are seldom cut back more than one third. The other method is practicable when the variety has the habit of producing new canes from the base and the bushes are widely spaced. It consists of taking the long shoots which grew the preceding year, bending them over in a wide arc, and fastening the tips to pegs driven in the ground. The semi-horizontal position forces buds to grow which otherwise would have remained dormant and results in a large number of blooms. Future pruning consists of the removal at the ground line of a sufficient number of the oldest canes to make room for the new shoots. A saw with a narrow blade (a keyhole saw) is a handy tool when cutting off old gnarled branches.
These blossom best on short side shoots (laterals) developed on the long, unbranched canes which grew the preceding year. They bear small flowers in large clusters and can be distinguished from the group to which the name "Climbers" is applied by numerous strong shoots originating at the base of the bush which at blooming time are 3 feet or more long. (Dorothy Perkins is perhaps the best known Rambler.) I prefer to prune this group just as soon as the flowers have faded, by cutting off at the ground line all canes which have flowered. The strong young canes, as many as are needed, are then tied up on the support. The remainder, if any, are cut off. If this was not done during August, it should be done in the fall or in the spring, and any shriveled cane tips cut off.
Climbing and pillar roses
These have a more permanent superstructure. Strong new shoots seldom grow from the base of the plant but instead come from branches several feet from the ground. Spring pruning, in the case of old, well-established plants, consists of the removal of worn-out branches (recognized by rough, dark bark and weak, twiggy growth) by cutting them back to the ground or to a strong shoot. The side branches which produced flowers last year are cut back to a length of 3 to 9 inches. Summer pruning consists of shortening new shoots which are exceeding their bounds. The necessity for this should be avoided as much as possible by planting strong-growing Roses, such as Dr. Van Fleet, only where there is plenty of room for them to develop.
Shrub and species roses
These include the Sweetbriar hybrids, the Rugosa hybrids, and species such as Rosa hugonis (Father Hugo's Rose), R. rugosa (Ramanas Rose), R. spinosissima (Scotch Rose), and others. Little pruning is necessary or desirable beyond the removal of dead branches. If the bush becomes unduly crowded, a few of the older and less vigorous branches may be removed, either by cutting them off at the ground line or by cutting back to a point where a strong new shoot is growing. The method chosen depends on which best serves for the maintenance of the natural habit and symmetry of the bush.
Summer pruning of roses
Pruning bush roses during the growing season is chiefly concerned with the removal of flowers for decoration and exhibition and the thinning out of their buds. This is a case where it is essential to know something of the habits of Roses in the various groups. Tea Roses and the Hybrid Teas that were introduced twenty or more years ago usually produce their flowers on fairly long stems with one to three flower buds on each. If there is one flower almost open and the buds are showing color, it is better to leave the largest bud, pinching out the other one. Roses for indoor use should be cut with the stalk long enough to serve its purpose as a cut flower and at the same time leave two or three growth buds.
If, however, the Roses are intended for exhibition, all the flower buds except one in each cluster are pinched off as soon as they are large enough to be handled. This must be done early; otherwise the wounds can plainly be seen and the judges will mark them as demerits.
In the case of those varieties which make candelabra-like flowering stems (many of the modern Hybrid Teas and the Floribunda and Dwarf Pciyantha groups), the central flower in the cluster is the first to open. This should be removed, usually with about 2 or 3 inches of stem. The buds remaining will open almost at the same time, making a good show in the garden.
The length of the stem to be cut when pruning in the growing season depends in part on the purpose of the pruner. If he wants a good showing in the garden, he should not cut the flowers with long stems, but if he wants quality rather than quantity, they should be cut with fairly long stems, leaving no more than two or three growth buds on the current shoots.
When garden roses are budded on Rosa multiflora, Ragged Robin, or Dr. Huey during July or August, some of them may start into growth the same season the bud was inserted. In this case the understock can be cut off right away. Usually, however, the scion (bud) remains dormant over the first winter. In the spring the understock is cut back as soon as the scions are showing new growth. Be sure it is the wanted Rose that grows and not the understock.
In preparing Roses for winter, if they are exposed to strong winds it is advisable to prune those which have made heavy shoots to sho. ten them; otherwise the constant whipping by winter winds may abrade the stems where they emerge from the ground.