Why do the stems of my knockout roses look reddish purple. Are they dead?
Usually this discoloration is meaningless; however, do watch for problematic rose black spot. When you do spring pruning, carefully examine the pith or center of cuttings. It should be a whitish color. There should also be a visible green ring just beneath the outside. If the pith is tan or darker and there is no green ring, recut the cane further down. I live in the north and some die-back is expected when winters are colder than normal. If you fertilized or pruned too late last year, your plant is likely to suffer die-back since it didn't have time to harden-off new growth. New growth needs about 6 weeks before frost to prepare for winter.