I don't have a knockout rose.. they're too common for me.
But when I do prune, I use a "Corona" 1" bypass pruning saw. Works great on roses, trees, (trust me on that one.. I took down a big ol' juniper with this & a Corona hand saw by myself in 2 days!), lilacs, fingers.. everything! I got 1 at my LGS, I got my second on Amazon.
http://www.coronaclipper.com/i...