Paul, I believe it may have been a past post you made about R. xanthina hybrids (at least it was one of our milder-weather members) that made me suspect that my R. rugosa X R. xanthina-type hybrids were inherently (nearly) unable to bloom. I have never observed any signs of spring freeze damage on either the plants or buds of these. They have shown a tiny improvement over recent years, from no blooms to 1 bloom to about 5 on 3 plants last year. I believe there are about 12 plants, total. I am hoping some bloom again this year, so I can at least examine their pollen. I expect they are sterile anyway, but I
Hi Roger,
It’s very curious to me that your rugosa X xanthina have never bloomed. I’m thinking that climate must at least be part of the problem, because my same hybrids have bloomed faithfully every year since the early 90’s.
I haven’t updated my website in a long, long time. But I’ll include a link to the old page I had on that F1 hybrid. As an update, I would no longer call this hybrid “not so vigorous” and it has also outgrown the dieback issues it had as a seedling.
It IS still very much yellow, spring-only-blooming and has never set a single seed yet; although I have had some evidence of it being pollen-fertile, when I tried backcrosses onto rugosa. Unfortunately I never got the seeds to germinate - but this was probably mostly due to my lack of attention to them - I was busy with other strategies, at the time.
Just another thought… was the rugosa you used, a named variety or a generic type? I used a generic type, if that might be part of the difference.
Tom
Tom, It
Hi Roger,
I’m glad I was able to inspire some crosses, but I would think that your hybrids should have had enough time to build up and bloom by now, too. That’s puzzling!
After some thinking, I’m wondering now if the climate/microclimate might be the key. I had three different locations in my parents yard, where I’d planted some of the F1 rugosa X xanthina seedlings. They all lived for a number of years (until I removed the plants from two of the locations) but in only one location did they really thrive. That is along the south-facing of my parents garage. That particular position is relatively hot and drier with poor shale soil. The seedlings I planted in this site have thrived, spreading underground to form a small thicket. They’re still there to this day.
So, I’m wondering what kind of conditions you’ve got your seedlings growing in? If you’ve got a relatively hotter, drier, poorer soil location, you might want to try it for some of them.
I’ll see if I can locate my more recent pictures of this hybrid and get them posted.
Take care, Tom
Perhaps we have more Rosa roxburghii hybrids than we realize. Debener et al. reported at the 2002 IHS Congress in Toronto that with AFLP analysis R. roxburghii was most closely related to R. foetida. R. foetida is suspected not to be a straight species and of hybrid origin by some. It is suggested within one of the Martin and Rix rose books. Perhaps Persian Yellow is of hybrid origin and R. roxb. is an ancestor. The form of PW sold by nurseries at least that I have had access too is triploid and nearly sterile. Some reported ‘Persian Yellow’ is 4x, but maybe they had a different clone or didn’t really do the work and assumed the ploidy level or used root tips, but didn’t realize they had a grafted plant. I used shoot tips as it is so difficult to root from cuttings. With the double flowers of ‘Persian Yellow’ and it being triploid and almost sterile, it is very likely not to be a selection of the straight species. It was probably an out of the ordinary clone selected and perpetuated. It could be a cross of the double R. hemisphaerica that is yellow and challenging to grow with something else. We know double flowers are dominant to single (at least the major gene controlling it and then minor genes control degree of doubleness). It has the high centers and rich color of R. hem. Hmm. It would be nice to know the form of R. foetida Debener et al used in their AFLP analysis. Perhaps R. roxb. from this AFLP analysis and the double form of R. hemisph. are the parents of our cherished ‘Persian Yellow’ which has been used to bring in rich yellow color to our modern roses and our hardy R. spinosissima hybrids.
By the way I confirmed ‘Austrian Copper’ is tetraploid.
David
Fascinating David. Thanks for these insights. I’ve heard rumored there are efforts afoot now to reorganize genus rosa both by Editors or Modern Roses and even perhaps by Martyn Rix using the collection at Kew.
I don’t envy anyone the task. I can’t imagine we can know anything truly definitive until authorities agree to accept a species standard based on DNA analysis?
Robert
Thank you David for the analysis. Robert, you are certainly right, about the necesity to use DNA analysis for phylogeny. I have believed for a long time that in fact it is R foetida bicolor that was used to bring yellow into the pernetianas, not Persian Yellow. Given the reported sterility of PY, and the tetraploidy with extreme fertility pollen of the Rf (Austrian Copper) that I had, I feel pretty comfortable making that assumption. Then recently I noticed the color and form of Condesa de Sastago (which I had many years ago) is really like my cross of A.C. onto Carefree Beauty, shown in the latest newsletter. Where else among species do we see such a striking contrast of petal surface colors? Which ancestor of C de S could have introduced that trait? Paul Barden’s Incantation has the same contrast, but with less of the underlayment of yellow.
I always assumed that it was Rosa foetida itself and neither Rosa foetida bicolor or Persian Yellow. I guess one could maybe rule this out to see if the subspecies, bicolor, is a superficial mutation or not.
I once got a seedling that looked a lot like Condesa de Sastago from a cross using Grey Pearl as the pollen parent. I’ll have to look it up to see what the other parent was. No idea where that red/yellow bicolor trait came from!
For this article, they essentially recreated the Pernettianas as an experiment:
de Vries D.P. & Dubois L.A.M. 1978. On the transmission of the yellow flower colour from Rosa foetida to recurrent flowering hybrid tea-roses. Euphytica 27: 205-210.
They used both R. foetida (single Austrian Yellow) and R. foetida persiana (double Persian Yellow). Both failed as females, but succeeded in making F1 seedlings when their pollen was placed on the white hybrid tea