Many years ago, my mother told me a story about a public rose pruning demonstration with three esteemed rose gurus. It was held on a weekend in a public rose garden and she watched how each of them pruned their roses. Each of them had their own special of doing it and some would cogitate for many minutes on each roses before actually doing anything. When the experts were finished their demo only ten or twenty of the hundreds of roses in this public garden had been pruned. So the following week, the team of gardeners came in and finished off the rose pruning, some apparently even used electric hedge trimmers. I can’t imagine they would spend much time deliberating over each rose, they would be on a mission to get as many done as quickly as they could. And the outcome? Well by the time spring was the roses all bloomed beautifully and it was hard to tell the difference between the pruning techniques used on any of the roses. The moral of this story has stayed with me and that is “have a go and don’t stress”.
Roses flower on new growth
Firstly, you must understand that roses flower on new growth, and all pruning does is simply stimulate new growth. There are two main groups of roses – those that repeat flower on and off from spring to autumn, and those that only flower once in spring. Spring-flowering roses include old-fashioned favourites such as Dorothy Perkins, Albertine and the banksia rose. These are not pruned now, but rather after they finish flowering, around November or December. Pruning these roses at this time will actually prevent flowering.
The right tools
Most gardeners grow repeat flowering varieties and these are best pruned over the next month or so. Firstly, get yourself the right tools. A good pair of thick gardening gloves is essential, as is a sharp pair of secateurs, a sharp pair of loppers and a sharp pruning saw. The emphasis is on sharp as blunt tools can not only make the job more laborious, but they can also be damaging to your plants. You also need a rag and jar with diluted bleach, or even a rag soaked in tea tree oil, to disinfect your tools between roses.
The first step is to cut out any dead, spindly or crossing branches at the ground or base of the plant. Crossing branches can cause an injury where they rub which can even lead to die back so remove one of the crossing limbs. Cut out skinny branches that are less than pencil thick as they will only grow skinny branches.
Then take off a third to a half of the plant’s height. Ideally prune just above an outward bud as this indicates the direction of the branch that will grow at that point. Next remove 50% of the canes from the base of the plant. New wood looks fresh and is lighter, darker wood is last year’s, and old brownish limbs are three or more years old. The aim is to completely replace the bushes framework every 3 to 5 years. This method is ideal for all bush roses including Floribundas, Hybrid Teas and Miniatures. If you are worried that it’s not a very healthy plant, take out only the dead bits and one old branch a year. Standard or stem roses need only have their heads reduced by 1/3 to ½ all over, again removing any dead, crossing or damaged stems.
There are a couple of principles worth bearing in mind when you are pruning.
Pruning technique effects flowers
The first is that the harder you prune, the bigger your flowers, but the fewer you get. Conversely, the lighter you prune the more flowers you get, but they are smaller.
Suckers vs water shoots
The second is to understand the difference between suckers and water shoots. A sucker is a vigorous growth from below the graft union and it is a shoot from the root stock. These should be removed from their point of origin by ripping them off, rather than just cutting them. Cutting them simply causes them to multiply and branch, like when we prune anything. So if you cut off one sucker, four will come back in its place, and on and on the cycle goes. Water shoots on the other hand are vigorous healthy new shoots that appear from above the graft. They are often purple in colour and should be retained even if they are outside of the shape of the otherwise pruned rose.
Clean up and feed
After pruning, clean up around your plants, removing the old leaves and prunings. The Rose Society of SA recommend that you give you roses a winter feed when you prune with a seaweed-based plant tonic, and cover with mulch.