When should I prune shrub roses in Willamette Valley of Oregon?
I was ready to start rose pruning in late winter (mid-February through mid-March), but have just read that in moderate climates, it is advisable to wait until 4 weeks before the anticipated last frost and that the last frost is predicted to be mid-May. That tells me that I should not start pruning until about mid-April. To add to my confusion, someone told me that the roses at the State Capitol have already been pruned. Could you please clarify optimal timing for pruning the following roses: shrub; hybrid tea; floribunda: and polyantha?
Marion County Oregon
Hi there. Wow not easy to find specific information on this one. There is lots of information out there, but I could not find a specific recommendation for the Willamette Valley. I decided to go on the Portland Rose Society web page and see what they had to say. Their general recommendation was late February to early March. They did not differentiate between types of roses but rather by the number of rose bushes you had. Those with lots of rose bushes they recommended starting earlier so that you could be done in time. Those with only a few bushes could wait a bit. I did find a University of Illinois publication that provided a bit more information on how. You may want to visit both places. Basically, if you prune too early the new growth that the pruning stimulates could be damaged by late frosts, those plants that are damaged by a late frost would then need to be pruned a second time. Here is the link to the University of Illinois article. https://extension.illinois.edu/roses/prune.cfm If you have any more specific rose questions you may want to browse the Portland Rose Society’s website. http://www.portlandrosesociety.org/links.html
Another good source of information is the Heirloom Roses website: https://www.heirloomroses.com/