I have two plants. One is growing like it is supposed to. The other one thinks it is a ground cover and is putting out 3-5 foot long runners like St. Augustine grass....or even like an octopus...Do you know what I can do to make it behave? Thank you.
It sounds like you got a mis-marked rosebush. This happens from time to time and the only things to do are to move the rosebush to a site where you can deal with the habits and go buy another knockout rosebush. Or did the rosebush out and take it where it was purchased, let them know of the problem and get a replacement rosebush. If you have had the rosebushes for a while and they are grafted rosebushes, then the desired rosebush you had has indeed died. The rootstock rosebush could be what is now growing and will be much different than the original.