Pruning season in South Africa extends from mid July to the end of August, depending on where you live. In cold regions pruning is usually done in July, but in very cold regions it is postponed until the middle or end of August. In the sub-tropical regions roses continue to grow in winter and can be pruned in August or September.
It is essential that you have the right pruning equipment and that the blades are clean and sharp. You will need a good pair of gloves, secateurs, a lopper, and for older roses a hand saw will come in handy. For larger cuts a tree seal can be applied; and a measuring stick, marked with appropriate pruning heights plus a bit extra added on the bottom so you can push it into the soil next to the rose you are pruning, will also be a great help.
Light Pruning should be applied to roses that did not perform satisfactorily last season or if immediate screening is required. Roses that are inter-planted with other shrubs will be competing with them for light and nutrients and should therefore also be pruned lightly. Light pruning is simple, quick and easy; and for those who are not that confident about rose pruning, it is probably the best method to start with. Tall growers can be cut down to about 90cm above the ground and medium growers down to about 60 or 70cm. Lightly pruned bushes will grow bigger the following season and will need regular pinching back. Because fewer stems are cut away the plant has more stored food reserves, giving it a kick start in spring; producing lots of leaves and therefore deeper and wider roots, making the plant more drought tolerant. The basal stems will also develop a thicker bark, thus protecting the stems from sunburn and stem canker. Light pruning is not suitable for roses planted closely together.
Severe pruning is the traditional method used and the bushes are cut down to 40 to 50cm above the ground. It rejuvenates roses well and is especially good for bushes with hard, woody stems. It is the preferred method used when roses are planted closely together. Pruning this way will produce plants of a more uniform height in the rose garden and will force the plants to produce long stems. A severe pruning knocks back the roots and the plants then need to be watered regularly during the season. If there is a drought and they cannot be watered regularly, they will not perform as well as they should.
Cutting correctly: Always cut back to a leaf or growth bud and make each cut at a slight angle, not more than 1cm above bud, this will ensure that the new shoot develops without die-back. Choose a healthy bud that is growing in the direction that you want the new stem to grow, but this will now always ensure that the plant shoots there - plants have a will of their own.
Aftercare is essential for healthy roses, especially severely pruned bushes. Open wounds can harbour infections and allow fungus to flourish, so paint the large cut branches with a tree seal before spraying them. If your plants were plagued by black spot, rust or scale infestations last season, mix 1 cup of Lime Sulphur with 8 to 10 cups of water and spray the bushes and the soil around them. Repeat 10 to 14 days later. Always use fresh lime sulphur and only spray onto totally dormant plants. You can substitute the lime sulphur by spraying with Ludwig's Insect Spray, which can be used on plants that are not dormant. Remove all old leaves that remain on the bushes as they can harbour diseases and ensure that the soil is well aerated, mulch with compost and apply a balanced organic fertiliser and a dressing of bone meal; watering deeply afterwards. In the summer rainfall regions water your roses thoroughly about every 10 days until spring.
Hybrid Tea Roses: First cut all the branches down by about one third and then remove all dead, weak or diseased branches entirely. Examine the inside of the bush and remove any very old wood at the base of the plant completely; leaving only about three to seven of the strongest basal stems. (Older wood has a darker and rougher bark). You should now have evenly spaced branches around an open centre. Remove any branches that are crossing one another and those that are thinner than a pencil. Now shorten the side shoots; always cutting to just above an outward facing bud.
Standard Hybrid Tea Roses: Prune as for Hybrid Teas, leaving about 30cm long stems on the plants.
Standard Floribunda Roses: These are pruned the same as for floribunda roses.
Miniature Standard Roses: Prune the same as for standard hybrid teas but cut them back even shorter, +- 20cm.
Umbrella Standard Roses: Cut off all the side stems and twigs, removing all dead, weak or diseased branches entirely. Examine the inside of the bush and remove any very old wood completely. You can then shorten the canes to your liking.
Floribunda Roses: Shrub roses are easy to prune and can be cut back roughly by about a third and dead, diseased or weak branches removed entirely. Cut out very old stems entirely to make room for the younger basal canes. Floribunda roses that are planted for a hedge-like effect should be pruned quite hard but those growing between herbs and perennials, lightly.
Upright growing Spire Roses: Spire rosescan be cut down to about chest height. Very old branches can be cut back completely to make room for the younger basal canes. Remove all dead, diseased or weak branches entirely.
Climbing Roses: Climbing roses include floribundas and hybrid teas. When these are about 3 years old, remove all ties and pull open the long branches in order to remove some of the oldest canes from the base of the plant, this will make room for the younger basal canes. Remove all dead, diseased or weak branches entirely. The remaining branches can then be pruned back by up to two thirds. If your plants are growing over a support like a wall, pillar of pergola, remember that canes that are trained to grow horizontally will flower better in October than those trained upright. Climber and rambler roses differ in growth habit, with climbers producing stiff upright stems, and rambler's long flexible stems. Ramblers include heritage roses that only flower in spring and early summer and are pruned when they have finished flowering. Cut out one third of the oldest stems at the base of the plant. The remaining shoots can then be shortened to restrain excess growth.
Miniature Rose: Miniatures are generally cut down to about 20cm above the ground and dead, diseased or weak branches removed entirely. To create a lower edging effect they can be pruned hard, down to 10cm. They can also be trained as small specimen plants if they are pruned higher, about 50cm.
Groundcover Roses: Clip with hedge shears and then remove some of the 2 year old wood with secateurs, to make room for the younger basal canes. Remove all dead, diseased or weak branches entirely and shorten the horizontally spreading canes.