Why Prune? There is more written about pruning roses than almost any other aspect of their care. Yet, why do we prune our roses? There are a few key reasons :-
encourage new growth and more blooms, improving the display in our garden
maintain the health of the rose by removing old wood, improve air circulation within the bush
maintain a specific shape, especially for climbing and pillar roses, and those that are pegged down.
Not all roses have the same need to be pruned, some need very little and an annual "going over" after flowering to remove the dead wood and encourage new growth will suffice. Other roses, most notably the highly bred Hybrid Teas and Floribundas, need regular pruning to encourage flowering and prevent the bush becoming 'strangled'.
If you garden on a light, sandy soil then prune your roses only lightly as they will not be able to support the vigorous new growth that hard pruning encourages.
Timing The time to tackle pruning is in the winter while they are dormant, before they burst into growth. In some areas of New Zealand, and in some seasons, there may seem to be almost no period of dormancy and so you must choose your moment carefully. Pruned your roses respond by sending out new shoots as soon as there is any warm weather. So do not prune when there is still a risk of severe frost, as any new growth will be frosted and die back. You will have to cut back to the next bud, reducing the plant further.
Tips You can prune your roses and wonder what went wrong come summer. Some tips to remember.
Tools for the Job Make sure you have the tools for the job. See here
Cutting The way you cut each rose cane is important. (See our diagram here)
Cuts should be clean - avoid hacking away, leaving a ragged stem end, and one more exposed to infection
Cut above an outward-facing bud to encourage the plant to grow into an open, vase shape. If the cut is too high the shoot will die back to just above the bud and there is an increased risk of disease.
Cuts need to slope away from the bud, allowing rainwater to fall away cleanly.
Pruning- How To Cut
What Type of Rose? Different roses need different methods of pruning, or you risk cutting off all the next season's flowers. If you don't know, find out.
Look first Look at the plant and study its shape and health. Remove old or diseased canes first, those that have been damaged (rubbing, ties cutting in, bent with wind) next. Check with any diseased canes that the stem end looks clean and white, not discoloured, after cutting.
Then prune for shape, (and it is much easier to see the 'wood' in the trees at this stage!).
Techniques For Each Rose Specific techniques apply to pruning different types of roses.
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Why does pruning work? The lead growth on a plant is known as the 'apical bud'. The apical bud produces growth-suppressing hormones that inhibit the growth of lateral buds, which that would compete for light and nutrients.
Removing the apical bud encourages the lateral growth and makes plants bushy, while removing the lateral buds concentrates energy in the encourage the lead growth and makes for stronger growth or larger show blooms.
R. 'Amber Queen'
A lovely bush rose that is especially suitable for bedding.
Tools for the Job
A really good, sharp pair of secateurs. To avoid infecting your plants, make sure that they are clean. If not clean with disinfectant.
Loppers will help with larger, stronger canes
A pruning saw may be necessary on really old, tough canes. (A regular saw is too bulky to get in where you need it and will damage other, healthy canes.)
A decent pair of strong gloves to protect your hands is worth the investment.
Armguards are worthwhile, especially with very thorny roses
Bush Roses
Most bush roses flower on the current years growth. A hard prune will produce more vigorous new growth and, usually, larger but fewer flowers.
Remove the oldest cane on the plant; this keeps the bush fresh and vigorous. Then reduce thick, strong stems by about half their height. Thin canes need to be cut back to one-third their height to encourage stronger growth.
Try to keep the centre of the plant open. A mess of spindly, twiggy growth in the middle of the plant restricts light and air circulation, encouraging disease.
Hybrid teas can be cut back to 20-25cm, although in warmer climates 45-60cm is advisable. Floribundas can be cut back to about 30-40cm
If you live in an especially windy area, pruning hard is even more important as it will reduce damage from wind-rock, which loosens the roots in the soil and reduces vigour.
