Steve - Can't help you with either KnockOut or Dorothy Perkins... don't have either rose. Actually, I can't remember seeing DP .. probably because it's a pink rose & I tend to ignore pinks. I get the worst winterkill on the hybrids, not so bad on the climbers. I think I only have 1 OGR - Camaïeux - everything else I have is a modern rose (would a polyantha be a modern or a OGR? I also have Heinrich Karsch, which is a poly). It also depends on how much snow I get.. the more snow I have, the less winterkill I get (snow insulates). But, for the most part, almost everyone croaks down to the ground (see this thread for examples:
The thread "My First Parade (JOKE!!)" in
Roses forum I remember spring when I lived upstate NY.. there was an actual difference between winter & spring! Here, there's no difference.. we go straight from winter to summer, then straight into winter again with very little autumn. That's why I have to mulch so damned heavily. But it seems to work (not to mention it improves my soil SOOO much!!) so, if ain't broke, don't fix.
