Larry Smith and the Riverside Gardens team talk about all things pots, plants and pruning in their weekly gardening column.
When you look at the gardens around town, it is hard to believe it is rose pruning time. Roses everywhere are still in flower even though the plants are looking a little worse for wear.
The late summer and warm autumn have meant our roses have almost forgotten to go dormant this winter, but don’t be fooled. It is time to start thinking about giving them a good prune back. The cold, frosty mornings we have had these past few weeks have been enough to send them dormant soon.
There are a few basic reasons we prune roses, the first being that roses flower in the first year and second year timber, so the more new seasons grow on the plant, the more flowers and the longer flowering period you will have.
Left to go, roses would become quite wild and unruly, putting their new growth on top of the old, and the plants would become large with most of the flowers up high out of reach. When pruning, we are trying to replace the older timber in the plant with new growth from down low, close to the crown of the plant, with the aim of replacing the timber on a rotating basis about every three years.
The first step to pruning is to make sure you have the right tools for the task at hand. You are going to need a good, sharp pair of secateurs, preferably a bypass pair where the blade passes by the anvil and does not strike the middle of it. Your secateurs do not have to be expensive, but they do need to be sharp and well-adjusted, and try to remember not to throw them out with the clippings.
This type of secateurs is more suitable for pruning soft tissue plants like roses. When using bypass secateurs, you should try to keep the blade-side of the secateurs facing the part of the plant remaining and the anvil striking the timber to be removed. This limits the damage at the site of the cut, and the bruised timber is left on the removed portion of the branch.
A pair of sharp, long-handled bypass loppers and a sharp pruning saw will also come in handy; these are much more preferable than taking multiple goes at cutting through bigger branches.
Once you have everything ready, start pruning by removing 40-50 per cent of the growth, just cutting away without paying much attention to where you are cutting. This has solved the biggest mistake most people make when pruning roses: by not pruning hard enough.
Next, look at what is left; it will be a lot easier to see what you have to work with now that the bulk of the rose has gone. We are looking for strong, healthy young stems that we can work with for the next season. Start removing weak and diseased stems in order, then stems that grow across other stems. Then, next are older stems, then crowded growth.
You should now be left with the strongest and healthiest stems on the plant, and we will select five or six of these to keep for the spring growth to sprout. Prune these remaining stems down to four or five buds high from the crown of the plant, choosing an outward-facing bud for our final cut.
The final cut should be made at about the thickness of the stem above the bud, cutting at an angle with the bud on the longest side and angled so that the finished surface of the cut will shed water.
When looking for buds to cut to, they are at every leaf scar on the stem. This is the mark left on the stem where a leaf was once attached. At this point, you will have one primary bud and at least two axillary buds to rely on.
The new spring growth will come from the top few buds on the stem, and the later growth will emerge down low from the base of the stems we have left. This lower new growth will form the stems that we can hopefully use next year.
Old overgrown roses can be cut back hard over a few seasons to work the new growth down lower each year to eventually achieve the same result. When pruning bigger branches, use loppers or a saw rather than hacking away with secateurs.
Once you have finished pruning, seal any large cuts with a wound sealant and then spray the rose down with lime sulphur to give it a head start on next season’s pests and diseases.
The same principles and techniques apply to pruning standard roses as they do to bush roses. But if you are pruning climbing or weeping roses, it is probably easier to call into the garden centre, and we can give you a quick run-through, as there are a few differences that will need explaining.
Apart from that, happy rose pruning. It is not as hard as you think, so it should not be a thorn in your side each year.