Hi, I have planted a new rose bush, which flowers a bouquet of roses per each stem, close to an older one, much much older. After 3 years the older rose, which used to have one flower per each stem, is now flowering a bouquet of roses per each stem and surprisingly also the roses are changing the aspect, looking more like the roses of the new bush. Can you explain me why? This is so curious to me.
Thank you for your question about roses. If you have the tags from either or both roses, please send us this information as it would be helpful in confirming what I think is happening.
Without a photo of the rose plants, I suspect that the new rose is a floribunda because of the description of a “bouquet” of flowers. (Floribunda roses produce clusters of flowers.) As well, the older rose, with only one flower per stem, sounds like a hybrid tea rose. Both varieties are widely available at garden centres.
Floribunda roses and hybrid tea roses are often grafted onto rootstock of hardier roses so that they can more reliably survive our cold winters. You can identify if your roses have been grafted by looking for the bulge where the graft union is formed. It might look like a knot or a tiny fist and is usually found below the level of the soil.
Sometimes part or all of the rose above the graft dies. The rootstock it was grafted onto may produce new canes (from below the graft) and these canes, also known as suckers, will flower in a different colour and/or form than the original top rose. This would explain why the form of your older rose is looking more like your new rose.
Please see the Toronto Master Gardeners’ Garden Guide on Pruning Roses to learn more about different types of roses and how to prune them. The Canadian Rose Society has information on different roses bred in Canada. If you want even more information on roses, a good resource is found here from the University of Missouri Extension.