RHA Newsletter 9(2):
Opportunities in Rosa foliolosa
Percy H. Wright
How does it happen that no rose breeder, to my knowledge, has ever attempted to bring any of the genes in Rosa foliolosa into the gene pool of our garden roses? This species, unique to areas in Oklahoma and nearby states, has a number of features which would be welcomed by rose lovers everywhere. And yet I have never read any discussion of the value of its genes.
One of the values is undoubtedly deep roots, which penetrate to a depth in search of moisture, a feature which would endear it to rosarians who wish to go off on midsummer holidays and leave their gardens unattended. Another feature is a tone of pink in the flowers which cannot by any stretch of imagination be called "rose". The tone we know as rose contains a touch of blue, but the pink, in the strain of foliolosa which I have seen, is clear of blue tones. The foliage, too, is different and most attractive, with small, delicate leaflets which indicate an effort to conserve moisture even at the expense of leaf surface.
Readers will ask, if I think crosses with this Texan and Oklahoman species rose are of promise, why do l not attempt to make it myself. The reason, until 1977, was that my plants did not bloom until mid-august, a date too late to expect any of our outdoor hardy roses to ripen seed. I could possibly have put the pollen onto greenhouse plants, but believe it or not, I did not think of this way out.
This year, 1977, did see an attempt by me to use the pollen of R. foliolosa pollen which was sent to me by a co-operative rose grower in the area in which the species occurs in the wild. I hesitate to give her name in case she should be overwhelmed with requests in 1978. This pollen gave me extraordinary results, when harvest time came, but whether good or bad is not yet clear, since they have not germinated.
I put the pollen on various Rugosa hybrids which would normally make 50 or 60 seeds per hep, but the heps resulting from the use of foliolosa pollen gave me 200 or more extremely tiny seeds. Will such tiny seeds germinate? By next March I should know.
My guess is that R. foliolosa is rather distantly related to other rose species, probably to all of them, and that if we want to make such crosses, the technique known as embryo culture may have to be employed. This technique involves considerable skill, and is certainly not for the home-grown rose breeder.
However, perhaps embryo culture may not be necessary, for I may be too pessimistic. I note in passing, though, that the technique might be used in making other crosses which have been difficult to make otherwise, for example, getting R. arkansana (suffulta) to accept pollen of Hybrid Teas. Has any rosarian as yet tried embryo culture in the hybridization of difficult roses? It seems impossible to believe that no breeder has tried it, because it has given such remarkable results in other genera. Perhaps some reader can enlighten me on this point.
But, to return to the topic of R. foliolosa the plants I have here have been hardy to the snowline, which would indicate that the species is relatively hardy. How did it gain any hardiness at all in a location so far south? One can only guess that in the prehistoric era when the glacial ice sheet came as far south as present-day Nebraska, the winters in Oklahoma and parts of Texas were more severe than they are now.
My plants have also been free of all the common rose diseases, but I can't state whether this freedom is due to a natural immunity or to lack of infection, since rose diseases, except rust, are not common on the Canadian Prairies.
If any reader, as a result of my testimony, tries to cross this neglected rose species with any other type of rose, in 1978 or later, I'd welcome a letter to tell me about the results.