I just now posted this to Facebook, and I see it's relevant here: "As you likely know, there was a lot of discussion in the late 1980s and early '90s (and still to some degree today) about "genetic decline" of roses -- the idea that "overpropagation" had made plants weaker and less desirable than they had been when new. And Peace was given as a prime example -- it had lost its pinkness and become more just pale yellow, as well as becoming far less vigorous than people remembered. I always doubted the idea of the mechanism, in that the "overpropagation" theory made no biological sense. Yes, if you make millions of copies of a rose, you'll see mutations among them. But they won't ALL mutate in the SAME way, which is what the overall degeneration seemed to indicate. Another concept, less popularly believed, was that it was one or more viruses that might be causing the overall decline. Again, a challenging concept, in that the whole population would need to catch the same virus(es). Nevertheless, we did discover, early in our heat-therapy work, that some older roses really seemed to be rejuvenated by the process, whether or not they tested positive for any known viruses. And Peace was one of them -- the heat-treated form was far superior (and in the memories of those who knew Peace back in the 1940s and early '50s, back to its good old self). I remember Mel Hulse exclaiming that the heat-treated form was Peace as he remembered it. So it is my suspicion (for which I have no further evidence or proof) that one or more viruses may be involved in this thing we call decline, in older rose varieties. And if heat therapy or some other method used to remove viruses is used, it MAY rejuvenate the rose. Alternatively, there may be some form of "aging" that happens in some (but certainly not all -- think Autumn Damask) roses, that is controlled epigenetically, and perhaps heat therapy resets that clock in some way. Pure conjecture of course; but at least we do have good, vigorous, pink-tinged Peace!" And oops, realizing this has been discussed on other threads, here, in the past. But I was reminded of the topic this morning with our lots-of-pink Peace flowering in our garden.