Trimming of Knockout Roses
by Daniel Childers
QUESTION: I own a landscaping company, and I had an employee trim the rose bushes to about 6" to 8" to the ground. I can't tell you enough I flipped out. Not to mention that this was for a very upscale subdivision. Will they come back, and how long will it be for them to bloom again. Thank You
ANSWER: Hi Daniel! Sorry to hear about your employee "butchering" the Knockout roses at this time of the year, of all things.
It pays to have a meeting with your employees and teach them when, and how to trim certain plants. They all have different pruning needs.
So to answer your question, I do think they will come back, even though this is absolutely the wrong time to prune, trim, any roses in Michigan. Ouch!
My advice is to mound the remaining trimmed canes with a foot of mulch for the winter.
Then, after the last frost date, remove the mulch, and wait until you see new growth emerging. Do not feed the roses for another 6 weeks when foilage starts to leaf out in spring.
Obviously, since the Knockout roses have been hard pruned in the fall, there is no need to prune now.
If you should see growth appearing soon, before winter arrives, it most likely will suffer from winter kill, and it could very well hurt the roses also, because they should have been ready to go dormant.
Rose pruning, trimming, has the opposite effect, it stimulates new growth, which is not a good thing right before winter arrives.
So only time will tell if the Knockout will survive the harsh winters in Michigan.
PS. Never trim roses before winter, ever.