With regard to Prairie Dawn, all I can contribute is that I grew it many years ago and it never did very well for me (Z3B), although some of the fault may have been due to the fact that the plant was budded and few of the root stocks used at the time were reliably hardy here. The plant struggled for several years–threw a tall cane or two that died back pretty far each year, and the plant ultimately failed–probably overgrown by more vigorous plants around it. I actually never saw more than a few blooms on the plant and any repeat was negligible, although that may have improved if the plant had done better. I kept one OP seedling from it–the poor thing had been placed in a sand pit for the winter and was somehow missed the following spring when I dug things up. I found it two years later–still in a 1-gallon pot–growing under a white pine. I felt it deserved royal treatment after several years of neglect. I moved it to a larger pot, gave it some fertilizer, and pampered it for a year before planting. The plant did not repeat, had a more Spinosissima or wild appearance than Prairie Dawn (but my Prairie Dawn was next to a double white Spin), and had OK but not great DR. On the other hand, it was completely hardy and very vigorous. I watched it for a few years but had other Spin crosses I liked better and I finally removed it. I suspect that any repeat on PD was of the type sometimes seen with the Explorers and many times that does not translate into a true repeat in the next generation.
What I feel to be the true Altaica stands out in several ways, although I have no doubt that there are probably several different varieties out there being sold as Altaica. The plant is definitely taller (~6 feet/2m) and more upright than many Spins and the blooms are noticeably larger. While not a true repeater, I had one early summer where it had the usual spectacular first flush–then about two dozen blooms later in the summer–and about half a dozen that bloomed in September–it only happened once and I have never had any seedlings from it repeat in a first generation even though it was my go-to spin for hybridizing. It is certainly possible that Altaica could be some sort of hybrid but there was never any doubt that all the seedlings I ever grew looked like Spin hybrids. The hips on Altaica are the classic Spin dark purple/black.
Prairie Joy will always be one of my favorite Canadian roses–yes, I have said this once or twice (or ten times) before. It is definitely not one of the hardiest and I lost two during a very harsh winter in 2002. Most winters result in 4-8 inches of live wood in the spring. Never-the-less, it regrows well to three feet (and throws the occasional longer cane) and I find the dense canopy of foliage a very attractive setting for the lovely blooms. It is not immune to blackspot but it tolerates the disease and due to the thick foliage it maintains an attractive appearance during the most severe infestations–while not common I have seen 50% loss of foliage but even under those circumstances the plant still looked decent. It seems to have better leaf-spot resistance than most roses I grow–some can be present but it is fairly minimal compared to what I am seeing all around it. While people argue about the level of repeat (or lack of repeat) I have grown it at two different locations over a period of 17 years and it always has a very good second bloom and definitely not the typical Explorer smattering of repeat blossoms. My experience echoes Paul’s with respect to juvenile bloom on seedlings. Interestingly, OP Prairie Joy seeds were some of my first experience with juvenile bloom from a hardy plant. I can still see those trays of seedlings in my mind so many years ago–especially since few of the Canadian hybrids I produced at that time had juvenile bloom. While I can’t say the exact percentages, I’d probably echo Paul’s statement of about 50% juvenile bloom for PJ seedlings. I have two seedlings with excellent repeat that are Prairie Joy F1’s, although I honestly can’t recall if these particular plants had juvenile bloom–they were produced 10 years ago.
While I agree with Joe that most of the Morden roses have not done well in my area due to blackspot issues, in addition to Prairie Joy I find that Morden Belle has proven to be one of my most reliable performers. It has shown excellent hardiness here with about 10-12 inches of live wood in the spring. It is a vigorous grower with a beautiful arching form, very attractive and abundant bloom, and a reliable second bloom. Yes, it gets blackspot and it can defoliate badly some years in later summer, but the canes are rarely affected by the disease and I have noticed that when blackspot seems limited to the foliage and does not seem to affect the canes that the plants can survive very well, year after year, even with the stresses of winter to deal with. I have only recently come to the conclusion that it is a plant that I would like to at least try and incorporate into my breeding efforts as it has so many positive attributes and the BS is something that it may be possible to breed out. In my experience it is not female fertile but the pollen is good. Cuthbert Grant is also a decent Morden rose with respect to health. The hardiness is a bit marginal in this area and it dies back to the crown but it always came back at my old location. The repeat was not heavy but was there. I just never got much from it–but then I didn’t use it heavily in hybridizing. Winnipeg Parks was a nice rose for years but in recent years the disease resistance to blackspot has broken down and it was never hardy here.
Paul, I’d recommend hanging in there with DKO or trying another plant. Mine took several years to establish well (perhaps a sandier soil makes a difference) but it is a standout performer now that the root ball has achieved some size. While only crown hardy, it is still one of the best plants I have and in my leaf-spot plagued site it is a stand-out performer with 5 years of testing. I do keep a couple inches of mulch on my beds and I was recently told that there is a huge difference in winter survival of plants in beds with mulch compared to those without. Perhaps my mulch has made a difference when conditions are so marginal and snow cover has been so erratic. I think that your (possible) Prairie Joy x Carefree Sunshine has excellent potential–what a great cross that could be. Both parents have so much to offer!
Joe, I am finding that a number of Ping Lim’s more recent introductions are surviving here and doing well in testing here–at least early on. The biggest problem seems to be that many are breaking down with leaf spot during the final year of testing. If LS is not an issue in your area then they are lovely roses, have lots of promise, and are definitely worth trying.