Question
Hi! My pink knock out rose bushes have white spots on the leaves and it is not mildew. The spots are only on the older leaves and other than that they are healthy and blooming.  I do also have some large canes coming out from the bottom of them. Are these not true knock out roses, since I didn't think the knock out rose would develop canes like a regular rose? I have been pruning them. Is that okay?

Answer
There are two different kinds of mildew, not just one kind. The white spots on your roses are mildew, just not the common one. Any rose fungicide will get rid of it. Mildew is cause usually by certain climatic conditions and so you mainly get it in the spring and early summer. The only other thing that could be causing whet spots are Rose Slugs as they suck the juices out of the rose leaves, but you would see them. Knock Ott roses are the same as any other roses and so will throw up thicker canes ode they get settled in. Don't cut them off as the rose bush needs them to survive.