In New Zealand, most roses are pruned between late June and mid-August, depending where you live. Don’t be tempted to start early as the roses will actually start growing again and then the new growth will get hit by the frosts, plus they won’t flower earlier if pruned earlier. Why do roses need to be pruned? First of all, it helps keep them to a manageable size in our gardens. It also allows old, dead and diseased growth to be removed and encourages the plant to produce more growth and, hence, more flowers for you to enjoy. Pruning also helps to shape the plant and open up the centre, allowing for more light and ventilation, which helps to minimise disease.
When making your cuts, make sure they are on an angle sloping away from the bud that will shoot into growth. Start around 5mm above the bud and slope back so the base of the cut is level with the bud. Take care to ensure the cut is clean with no ragged edges, otherwise dieback can become a problem.
You can control, to some degree, which way your rose will grow by cutting to a bud pointing in a certain direction. In most cases, cut to one facing outwards but sometimes the strongest bud is facing inwards so it is best to cut to this.
If removing canes from right down at the basal union, do not leave any stubs behind as this can cause dieback to occur. Always remove canes flush with the union.
Pruning climbing roses
Pruning a climbing rose (from top left): before pruning old shoots and dieback removed cane tied horizontal side canes after shortening to two-three buds (above) end result of pruning.
Many people make the mistake of treating their climbers like bush roses and cut the long stems back each year and then wonder why they are not climbing. You want to train them horizontally along the wall or fence so you get blooms along the length of the stems. Ideally climbers should be trained into a fan shape. The stems are surprisingly flexible and there is little chance of breaking one.
If climbers are growing up a post where they have to grow vertically, what you can do is retain the long canes and wrap them around the post. Cut back side growth to two-three buds but also stagger the height of the canes so you get flowers all the way up the plant, rather than just at the top.
Pruning bush roses
These include hybrid tea, floribunda, David Austin, shrub and miniature/patio roses. For these types of roses, you want to reduce the plant by about half in size – do not try to make a large rose “smaller” as it will only do what it naturally wants to do – grow. First, remove any dead or diseased stems then take out any twiggy or weak growth. Then remove any old stems, although sometimes you don’t have much choice and have to keep them in place. Old stems are usually a grey-green colour and rougher in appearance. Young stems are smoother and are brown, red or a brighter green colour. Remove any stems that are crossing or rubbing together. Sometimes you can push them apart with a spacer made from a piece of pruning material with a notch at one end.
Now thin out any crowded stems, particularly those in the centre of the plant. Then shorten any remaining stems by half and you are done.
Obviously with miniature/patio varieties, things are done on a smaller scale.
Top tips for rose pruning
- Always prune on a day that you could get your washing dry.
- Sharpen your secateurs and other tools before you start pruning.
- You don’t need to apply pruning paste or similar products to cuts on roses. The best thing to do is allow the wounds to heal naturally.
- Winter clean-up sprays can be applied after pruning but wait a few days after you prune. Copper is good for cleaning up the disease spores that are present around the plants while oil will assist with controlling scale. Check the packets for application rates.
- Burn or dispose of rose prunings. Do not put them in the compost.
- Once finished, give the basal union a light scratch with a wire brush. This removes flaky bark, lichen and moss that has built up around the union. New basal shoots emerge from here and are the life blood of your rose bush. Just scratch carefully so you do not damage any emerging shoots.
- Once you have finished pruning, pick up all the fallen leaves from around the plants and fork over your soil.
Prune standards as you would bush roses but prune harder as they are further from the ground.
Older stems may also need to be kept longer as standards generally produce fewer new shoots than bush roses. Check ties and stakes, making sure the ties are not cutting into the trunk.
Pruning standard roses (from left): before pruning make sure the stake isn’t cutting into the stem the stake should be higher than the graft after pruning.
These are roses grown as standards that produce long shoots that droop towards the ground. Retain these long stems and just remove any dead or spindly wood.
Old-fashioned and species roses
Very little is usually needed with these roses. Just remove any dead or diseased stems and then trim to shape the plant.
Once-flowering varieties should be pruned after flowering has finished.
For pruning most roses, you will need a good pair of secateurs and gloves to ward off the thorns. For larger canes, a pair of loppers or a pruning saw will come in handy. If you are pruning climbers and standards, it is also helpful to renew ties as you go, so some ties will also come in handy.