Stephan, we were there on Saturday early afternoon until almost closing time. I found just a small handful of hips on HY earlier in the afternoon. I learned later that day that taking plant flowers/material/seeds is not permitted so I appoligize about taking the hips. I had hoped to take more hips from other rose specimens but stopped when we learned about the rules. We spent a good deal of time going through the Asian Collection and enjoyed it very much. One of the highlights for me was the koi pond which has some HUGE koi. Having them eat almost out of your hand was a pleasure. There were some young children that were thrilled by that experience. I envy you working at such a wonderful site that has so many fantastic specimens of plants. I will go to the web site and read your article. I thought that any seedlings that show promise would be good to cross with something like ‘Hansa’. R. glauca or hybrids was another thought.
Great article Stephan. 
Thank you, Rob! It is a pleasure to work there, and I have wonderful coworkers, too. I’ve added a lot of roses to my section but most weren’t labeled yet - I do hope you found it all interesting. I just noticed a huge flower cluster starting on my Ensete glaucum (a Himalayan snow banana), which is quite exciting to see even though it’s hard to imagine it will fruit successfully before the end of the season. The koi are quite fun - can you believe they sold off about 1,000 of them from that pond just last year? They reproduce like cockroaches
I like your ideas for crosses, too. R. glauca itself can be a disease magnet of sorts depending on the garden (if you saw the one-cane wonders with no leaves here, you probably know first hand), but perhaps it could be a great combination with ‘Harison’s Yellow’. It seems to me I’ve read about someone crossing it with ‘Hansa’ before with quite interesting results, color-wise; I think you’ll have fun with that one.
I haven’t used ‘Hansa’, but I’ve crossed R.glauca with typical R.rugosa (using rugosa as the seed parent). I got two color-types from this cross – a dark-fuchsia pink (darker than the rugosa) and a medium pink (intermediate between the two parents).
These offspring should be diploids, unlike the reverse cross, which gives tetraploids (like ‘Carmenetta’). They’ve been relatively fertile for me. I think repeating the cross using improved rugosas (doubleness, color, etc.) would be very worthwhile – but I no longer have R. glauca. I’ve tried replanting twice, but both new plants of glauca have died. I guess I’ll have to keep trying.
Stephan, there is so much to see at the arboretum that it is almost overwhelming…in a good way. I can’t imagine what that pond looked like with an additional 1,000 koi. At the prices I’ve seen for koi, selling them is a great way to raise funds for desired projects. I did notice the glauca one-cane wonders. lol
Tom, how was the bloom size on the hybrids you raised? Did the flower size improve over glauca’s flower size? I’m assuming that I’d be taking the long way around but I was thinking of R. glauca x R. rugosa (diploid) and crossing promising seedlings with R. glauca to get a tetraploid hopefully with the desired blue/grey leaves. Then I’d move forward to work towards repeat bloom. I would also go the route of R. rugosa x R. glauca to get the tetraploid and move forward on that line as well.
Rob,
The blooms were intermediate in size between glauca and rugosa.
And I don’t think I understand the strategies that you mentioned – glauca(seed parent) X rugosa should give tetraploids with bluish foliage already (‘Carmenetta’ for example). Rugosa X glauca gives diploids with bluish foliage (like my seedlings).
I don’t think that either way has the intensity of foliage color of glauca, but my gut feeling is that repeat bloom might be harder to recover than the foliage color.
My website’s in a state of disarray, but I threw together a page so you can see the two color forms of rugosa X glauca.
Tom
Tom,
Sorry for the confusion. Reading my strategy again it looks like it doesn’t make sense. It did at the time. lol I think what I was thinking at the time was rugosa x glauca, as you mentioned, produces a diploid and then using promising F1s to cross back to glauca producing tetraploids that hopefully reinforce the glauca coloring in the leaves. Does that make sense?
Thanks for posting the link to your rugosa x glauca seedlings. You’ve had some great results!
Hey Rob,
No apologies necessary. Confusion is my normal state of mind {grin}. And I now I understand your strategy, I just don’t know if I would go that route. {Now, I’m laughing out loud!} So… you’d have glauca derivatives [tetraploid] with introgression from rugosa, right?? Like I’d mentioned, I think you’d have a hard time getting back repeat-bloom, but I could easily be wrong.
I have 4 or 5 backcross seedlings – (rugosa X glauca) X rugosa. I was hoping for kind of the reverse of what you’d be doing – essentially rugosa derivatives with some introgression from glauca. Hoping that, being mostly rugosa, at least some would rebloom, and that I could interbreed among those rebloomers expressing the most glauca foliage traits, to try to intensify those traits. My vision is of a rugosa with glaucous and/or purple foliage.
So far, one of the backcross seedlings has decent “glaucousness” but none have shown any signs of repeat yet (actually no bloom at all yet). Maybe that’ll come with age.
In any case, if you have glauca, and you’re mulling over what crosses to make with it… I’ll repeat my suggestion that you try combining it with some double-flowered rugosa, in either direction. A double-flowered ‘Carmenetta’ type would be really useful; it should be able to produce 2N gametes - for direct infusion into the tetraploid gene pool.
A double-flowered (rugosa X glauca) F1 could be used just like I’m using my single-flowered seedlings, to introgress glauca traits into the diploid rugosa gene pool, but with the added value of doubleness.
Good luck however you decide to go.
Tom
Thank you for your message Tom. When it comes to ploidy counts and what to cross with what that is when I’m in my normal state of confusion. lol Your point about having a hard time gettin back repeat bloom is well taken. So is the point about using some double-flowered rugosa either way. My overall goal is to obtain the most glaucous/purple foliage that I can in a repeat blooming tetraploid. I thought of using rugosa as the other parent to bring in genes for repeat bloom, hardiness and disease resistance. The leaves wouldn’t necessarily have to be rugose. Obtaining ‘Carmenetta’ would probably be the best way to start the process.
I appreciate the suggestions you have made helping me sort through my thought process. Good luck with your efforts in this area.
Rob