I have just been doing some reading on warm climate rose breeding (here: http://greatrosarians.com/weblog/?page_id=250 by M. S. Virarghavan). In it he says that "Jack Harkness described this rose [gignatea] as having six great virtues
Another question re: gignatea crosses… do they need cold stratification or will warm stratification do just fine? Or can they be sown immediately after harvesting?
Rosa gigantea is not remontant, as such; perhaps Mr. Virarghavan was referring to the book that is linked below, where Harkness refers to R. gigantea having “four important characteristics,” one of those being “a long period of flower.”
I know that some books say that the native chinensis, not specificially the cultivars we have for sale, can be repeat blooming or once-blooming giants. Maybe the same can be said for other SE Asian species such as gigantea…
Which reminds me, I wish I had the wealth to see what is left of China and SE Asia’s rural areas, which seem to contain a lot of the world’s horticultural beginnings…
Gigantea can give scattered repeat, as will certain other species considered once blooming in some climates. This occurs along the the California coast, especially on well established plants.
Banksia often do the same thing.
So do the hybrid gigantea seeds need cold straification?
I have no experience germinating this species, so I can only give a common sense recommendation – but I would guess that they might germinate at least partially without cold stratification. However, even if they do benefit from cold, it won’t hurt to give them a warm stratification first, at which time you can watch for early germinations. If you have none after one to two months, then try a period of refrigeration. Hybrid seeds could vary in their requirements due to the influence of the pollen parent, so your best bet is probably to simply try and cover all bases by starting with a warm treatment before going to cold. Those are my two cents, anyway.
Gigantea seeds are very large as are sp chinensis spontanea ones. The largest seeds I know and very difficult to germinate at least for me.
As a rule the larger the seed the more difficult to germinate. It is also the smaller the easier…
I’ve been looking at Viru Virarghavan’s work with gigantea and notice that Evergreen Gene is a HT x gigantea cross and he has got remontancy back in this F1 cross… If remontancy is recessive then one would expect NO remontancy in the first generation when crossed with a once flowering gignatea… unless there is something else going on…
‘Evergreen Gene’ is not remontant. See comments.
OK… so I guess the “Blooms in flushes throughout the season” on HMF refers to growing it in India in the subtropics…
“Blooms in flushes throughout the season” on HMF refers to growing it in India in the subtropics"
Nope, it is non-remontant as far as I know. HMF needs to be updated. I expected it to be after I made that comment some time ago but apparently they haven’t gotten around to it.
They can verify accuracy with the hybridizer.
Cass, help?
Thanks Robert 
Have you used Evergreen Gene in any crosses yet? I’m not familiar with its HT parent; Carmosine… does anyone know anything about it?
‘Evergreen Gene’ is sterile according to it’s creator. I don’t even have it anymore. I gave it to Roses Unlimited and Cool Roses then discarded the original plant.
It was a beautiful thing but just too large to keep long term, especially since it is once flowering and purportedly infertile. It would look great on a large tree or pergola. I also had another unique cultivar budded to the same stock and I had to remover EG in order to force it. We all have to move on.
‘Carmosine’ is reported to be a red HT. It purportedly does well in warm climates like India. That is all I know. I’ve asked for more information but got no response. I have a feeling this was a chance lucky cross that Viru exploited since it has fertility as pollen parent.
I meant to mention earlier that ‘Amber Cloud’ supposedly will repeat. It didn’t here in the time I had it but the I never allowed it to get overly large. (That’s saying something!) It’s gorgeous.
I hope to utilize ‘Manipur Magic’ this season.
You guys are so lucky to be able to obtain these specimens to work with. We do get new varieties in but never the ones that interest me… a lot of the ones you guys mention here are unavailable so we need to go back to their parents to see if they are here and repeat the crosses hoping for something remotely simialr. ‘Amber Cloud’ does not appear to be here though I haven’t exhausted my search options yet… oh well…
These cultivars are just being distributed Simon so don’t despair. You need to find a supplier there that will work to obtain new varieties. Surely you aren’t the only one that would be interested. Do you have access to gigantea?
Yes… as of today! Have just received cuttings from a contact in New South Wales…
Great, now you can start to experiment. Budding can accelerate flowering.
I assume you mean of any resulting seedllings???
Gigantea sometimes doesn’t flower till it gains size. Perhaps in your climate you will be fortunate enough to get flowering relatively quickly.