Usually I prune my roses towards the end of June, but at the moment with the seasons changing and the fact that they are still flowering, when is the best time to prune and do you have any other advice on treatment during the colder months?
It is imperative that you delay pruning your roses until they have become completely dormant; ie: leaves no longer present on the plant. Pruning any earlier with the very mild autumn we are experiencing may result in new growth appearing which will then suffer when the cold weather eventually arrives.
Pruning roses may well now be a July task. You should still apply winter clean up applications of a copper compound at any time during the next few months however, regardless of whether there are leaves on the rose bushes or not.
When you do prune, ensure you remove any dead or diseased wood, and prune out all inward growing branches and shorten all other branches back by at least half or more. (Note: this is dependent on variety). Prune to outward facing buds and always make clean cuts with no straggly ends. One week after pruning, spray with Lime Sulphur and/or a copper compound such as Copper Oxychloride to ward off fungal diseases (do not mix these sprays together). Then, 3 or 4 days later, apply a horticultural spray to kill off any overwintering pests (again do not mix with copper).
Products to try: Daltons Premium Rose & Flower Fertiliser, Daltons Premium Flower Bed Mix.