- Pruning is essential, as is encourages new growth in roses, and therefore more flowers.
- July until early August is the time to do it.
- Don’t prune during frost as your rose will be damaged.
- Have your tools ready before you start.
- Cut roses back to a minimum of one-third of their pre-pruned size.
Rose pruning can be daunting. It seems dangerous, difficult and possibly terminal for the plant. If rose pruning worries you, the bad news is at some point you reach that date on the garden calendar: pruning season is July–August. The good news is, don’t panic because here is your pain-free guide to rose pruning.
It helps to know why you are pruning in the first place. Roses are pruned to encourage new growth, which in turn encourages lots of flowers. Keep that in mind and the entire task of pruning will seem much more rewarding.
Pruning rules for roses
The most common pruning error is to not prune hard enough. The winter pruning time is when all the mess and clutter is removed, leaving a basic framework for the rose to renew itself in spring.
When to prune your roses
In our climates, winter pruning is done in July or early August. Leave it until the later date if your garden experiences frost. By July, new growth may be appearing, so get out the secateurs and start to prune away the old growth.
Where frosts occur, delay pruning so new growth will not begin until after the frosts have finished or your rose will be damaged.
While most roses do the right thing and go dormant in winter, some refuse to stop flowering. ‘Iceberg’ is one that flowers well into winter. Don’t worry about a few lingering flowers. Cut them off and get on with the pruning.
Some roses don’t get pruned in winter. Any roses that only flower in late winter or spring are left until after they’ve flowered before pruning. If you make a mistake, you will reduce flowering. Hold off pruning banksia roses, most of the old-fashioned roses, some climbers and most ramblers.
How to prune
Before you begin pruning, assemble your tools — clean, sharp secateurs, a pruning saw, a drop sheet or large bin to hold the prunings, and thick gloves. Also have on hand a disinfectant to sterilise the pruning tools before you begin and as you move from one rose to another.
How far you cut back depends on the size and vigour of the rose and where it is growing. Cut most roses back to around one-third of their pre-pruned size. Tall, fast growing roses can be cut back harder.
Go over the rose, cutting everything back by about one-third. Remove any lingering flowers and leaves. Remove any suckers (growth from the root system below the graft). This makes the rose more accessible for more detailed follow-up pruning.
Next, remove any spindly growth, dead branches and very old brown or grey wood, cutting all this unwanted growth off low down on the plant. Use the pruning saw to cut thick stems.
Select three or five green, healthy, vigorous branches as the framework for the next season’s growth. Remove any other unwanted stems and then cut back the framework branches to an outward facing bud. An outward facing bud is selected to encourage growth away from the centre of the plant.
Remove all the pruning debris, including fallen leaves and flowers from earlier in the year. Spraying roses after pruning with lime sulphur is essential to control pests and diseases such as black spot. The spraying is done immediately after pruning as, if left, it will burn new shoots.
With pruning and spraying completed, renew the mulch around your rose with a 5cm layer of organic matter such as lucerne, sugar cane, compost or manure. Water well when new growth begins.