A dry day in June or July is the perfect time to prune roses.
Before you start, take a moment to study the existing shape, and think about the shape you are trying to achieve. With rose bushes, aim to remove between 1/3 to 1/2. Piling your cuttings next to you is a great way to keep track of how much you have pruned.
Start by removing any dead, broken, or diseased branches. When removing diseased wood, clean your tools after each cut with rubbing alcohol or diluted hydrogen peroxide.
Next prune out undesirable branches such as crossing or weak branches, suckers, sprouts, or those branches which are too long or too low. Generally anything thinner than a pencil should be removed.
Then prune the remaining canes by cutting around 1cm above an outward-facing bud; make cuts at a 45-degree angle sloping away from the bud, allowing water to run off.
You can prune harder with a standard rose, leaving each branch about 20 cm long. Once you’ve removed the dead, diseased, broken or small and spindly growth prune the main branches so the standard head forms a vase shaped with at least four (ideally five or six) strong leaders with outwardly facing buds. Leave the inside of the crown nice and open.
Climbing roses are slightly different. For the first two years, climbers should receive little pruning except to develop the desired framework of canes. The younger strong shoots should be attached to the support to fan out evenly. It is the laterals from these canes which will bear next year’s flowers. Mostly, winter pruning of mature climbers consists of shortening laterals to two-three buds from their main base. Again, start with the removal of dead, diseased or broken canes and laterals.
With any type of roses, once you have pruned, it’s important to makes sure the ground below is clear of leaves and pruning debris. If your roses have suffered from blackspot or other fungal disease then spray them with copper straight after pruning and again a month later. It is important to spray the whole plant as well as the soil around the base.