Knockout roses bloom good start last year then only a few. Plants looked...
Hi Franklin County, I have discussed your question with Mike Ecker at Dawes Arboretum to see if they had similar problems. You have not mentioned where the roses were located - full sun, in a bed, at the edge of the walk, etc. My first guess on the problem has to do with the season last spring, early summer. We had a LOT of rain over that period of time. My thinking (and Mike's too) is that the rose bed is near the lawn or an area that was fertilized. The rain has moved the fertility into the root zone of the roses enabling a lot of great green growth. When you have that situation, then you don't have quite so many flowers.
As for a remedy, I don't know because I can't see the situation but I would suggest trying not to broadcast fertilizer (especially high nitrogen fertilizer) into the flower bed. Maybe the fact that they were recovering from the previous winter and summer means that they put on a lot of good growth so that this spring and summer they will be producing a lot of great blooms.
Hope this helps. Don