I’m remembering reading (but can’t remember where) this is the most cold hardy rose Harkness created. It’s always been quite disease resistant for me, but until Encino, what wasn’t? Has anyone played with this one and what, if any, were the results? Kim
I’ve done a few crosses with it over the years, but never got anything worth keeping from it. It is very disease resistant for me too, and I’ll probably try it again.
As I recall, it wasn’t very hardy in my Minnesota garden relative to most roses I grew–and (coincidentally or not) it didn’t keep that many leaves, either. Of course, the relevant standards might be slightly lower almost anywhere else, but I would hate to think that all Harkness roses are so doomed 
I’m afraid it didn’t survive long enough for any breeding experiments, though…
On a related note, there’s always that tricky correlation between disease resistance and winter survival/spring rebound in climates where hardiness matters. A healthy rose is going to fare much better even when it’s cold tender, and a sickly rose is still going die even if it has arctic hardiness!