Several years ago a rose-pruning trial, held in conjunction with the Royal National Rose Society, showed that a group of roses that had been carefully hand-pruned flowered just as much as a similar group that had been cut down with an automatic hedge-trimmer. Since then, whenever I’ve been pruning roses, there always seems to be some smart-Alec non-gardener around to recount this story to me. But the point about pruning roses is not just to encourage lots of flowers: it is about producing a healthy, attractive and long-lived plant. And you don’t get that with the swipe of a hedge-trimmer.
The first task, whatever the type of rose you are pruning, is to take out any dead or diseased stems, which should be removed at their base. Damaged or withered stems should be cut back to a healthy green shoot. When you cut through a rose stem it should be clean and white. If it is black or has a dark centre cut again further down the stem.
Pruning roses can be done at anytime between autumn and early spring. Doing the job early gives you a neat plant through the winter that doesn’t harbour disease and that won’t be injured by high winds. The root system of roses is not as extensive as most other shrubs and plants are susceptible to ‘wind rock’. The problem with early-pruning is that frost can damage the newly-pruned stems. To get the best of both pruning regimes I prune my roses in two stages: they get a first prune in early winter to clean them up and reduce their height, and another, to finish the job, in the spring.
The autumn work begins with tackling free-standing shrub roses that have become congested. Cut out very old, woody stems at the base using a pair of long-handled loppers. To encourage better flowering, and to reduce the plant’s susceptibility to disease, you need to create a plant that is open in the middle. This will allow light and air into the shrub. Cut off any stems that are growing diagonally across the centre of the shrub and any that are rubbing against each other. Next, chop off the top one quarter of the rose’s growth. You don’t need to worry at this stage about where you cut. The following spring prune the top stems to a new bud that is growing away from the centre of the plant. Using sharp secateurs cut just above the bud at an angle of about 45 degrees, with the blade sloping away from it. Smaller side-shoots should be cut back to two or three buds. Thorns can do a lot of damage, so wear thick gloves.
Shorter hybrid tea and floribunda roses need to be pruned back to about 45cm high, which means shortening the shoots by one third to a half of their length. Again, cut just above an outward-facing bud with a sloping cut. Thin stems – those that are about the diameter of a pencil – will not produce many flowers. Cut them back close to the main stem to stimulate stronger growth. These roses are often grafted onto the top of a tall stem to create a standard rose and should be pruned in the same way as you would if they were grafted at ground-level.
Miniature, or ‘patio’, roses have none of the exuberance one usually associates with roses but are, nevertheless, very popular. Their pruning, like their charm, is minimal. Remove the dead flowers as they fade, cut out desiccated stems in the autumn and trim the whole plant by about a third in the spring.
Suckers on roses
Most roses are budded or grafted on to the rootstock of a wild rose. Occasionally a rose will produce stems from the rootstock rather from the grafted plant. These are called suckers and are very vigorous. Left to grow they will dominate the whole plant, leaving you with a wild rose rather than the elegant hybrid you originally planted. The swelling at the base of the stem at soil level is the place where the rose was grafted. Shoots appearing from below ground or underneath the grafting point are probably suckers. They are usually fatter than grafted stems, covered in more thorns, and have seven leaves rather than the five typical of grafted roses. To remove them, follow the stem down to the point it grows from, clearing away the soil if necessary, and pull it away. If you cut it down rather than pull it off you will only encourage more shoots.
Removing dead flowers not only makes a rose look more attractive but also reduces the problem of diseases such as botrytis. Use secateurs or florists’ snips to cut the flower and stem off at the second or third leaf-joint below the flower. This will prevent the formation of seeds, so do not deadhead species roses, such as Rosa rugosa, that are grown as much for their hips as for their flowers.