The Canadian Rose
Annual (1967) pp. 102-104
Progress in Hardy Everblooming Roses
PERCY H. WRIGHT
IT wasn't too long ago that a writer in one of the American Rose Society's publications stated categorically that the combination of hardiness and everblooming in rose plants was impossible, and that the search for it was futile. At the time this article was written, varieties which possessed the combination were already in existence.
The roses which have combined hardiness with everblooming are mostly rugosa hybrids. Of all the northern species which are capable of transmitting hardiness to their progeny, rugosa exhibits the most remarkable ability to do so without loss of fall bloom in the hybrids. It is possible that suffulta may be an exception to this statement.
As Dr. W. Van Fleet pointed out in an American Rose Annual published before 1920, rugosa reveals certain highly dominant characters which are the price paid for the combination of hardiness and everblooming, particularly short and weak flower stems and excessive thorniness. Even after rugosa has had repeated infusions of the genes of other tender roses, to the point that practically all gain of hardiness is forfeit, these undesirable features persist to, some extent. Dr. Van Fleet was of the opinion that the breeding of Rugosa Hybrids had at that time reached a cul-de-sac definite enough to suggest that some other approach should be attempted.
Since 1920, hybrids between Hybrid Teas and numerous species roses other than rugosa have been made, and from the crosses much experience has been gained. In general it has been found that the genes of these other species do not result in the transmission of so many undesirable features as the genes of rugosa do, but that they dominate the hybrids much more as regards June blooming. In other words, the combination which is really sought is threefold, hardiness, everblooming, and a large number of good qualities. Naturally, a triple combination is much harder to achieve than a double one — especially when the third one is itself far from simple.
How do the Rugosa Hybrids, or some of the more remarkable ones among them, manage to achieve the combination of hardiness and everblooming which was assumed to be impossible? In seeking an answer to this intriguing question, let's look at the well known rugosas Hansa, Mrs. Anthony Waterer, and Kamschatica, all rather similar and all remarkably hardy.
The secret of the combination appears to be in the ability of these varieties to use the first light frosts of autumn as warnings to harden up their tissues for the much deeper freezes to come. June-blooming roses do it by ceasing to grow and produce blossoms and new wood as fall approaches, but the everblooming roses are automatically denied this "normal" method of attaining dormancy.
One year in the early 1950s, when the writer lived near Carrot River in northeastern Saskatchewan, warm weather persisted to October 15, and Hansa plants were in full bloom and actively producing buds at that date. Then the winds changed direction, and the winter descended all in one foul blow. That year the Hansa roses were killed to within an inch or two of the ground, and many other roses normally hardy were injured also.
The prairie tetraploid species, suffulta, easier to blend with Hybrid Teas to produce fertile or partly fertile hybrids than rugosa just because it is a tetraploid, has recently been used in crosses with both Hybrid Teas and Floribundas, crosses which seem to be easy enough to achieve if suffulta is used as the pollen parent. One of the most interesting of the Suffulta Hybrids, Assiniboine, was originated when H. Marshall of the Brandon Experimental Farm put pollen of suffulta on the pistils of Donald Prior. Assiniboine is of very different character from the rugosa hybrids, and better in several important characters. It is, however, less hardy than Hansa. When moisture is sufficient, it re-blooms profusely in August, at least in the latitude of northern Saskatchewan. Since its male parent Donald Prior is only a semidouble, Assiniboine is semidouble too. This defect will almost certainly be remedied in future breeding.
The species suffulta is really a remarkable one, since in its natural and unimproved state it too combines hardiness with fall blooming. Its use in making hybrids with Floribundas and Hybrid Teas is too recent to say definitely what its limitations are likely to be. However, the reduced hardiness of the first-generation hybrids is pronounced enough as to suggest that second-generation hybrids (three-quarters tender rose and one-quarter suffulta) will not be nearly hardy enough for the climate of the prairie provinces, although it may be enough to bring joy to rose growers in climates where winters are only a little too severe for Hybrid Teas.
This assumption suggests that, as far as the colder areas of Canada are concerned, further Suffulta Hybrids will have to have at least as strong an infusion of suffulta genes as Assiniboine itself, even though they may be segregates in the second generation.
But what possibilities remain for the use of rugosa in the breeding of hardy everblooming roses? It would appear that if Rosa rugosa is first crossed with Rosa blanda, and then this hybrid is bred to Hybrid Teas or Floribundas, the dominance of rugosa's weak bud-stems and excessive thorniness is broken much more effectively than if repeated infusions are made with the tender roses to a similar degree of loss of hardiness.
The rose Therese Bugnet, which most of us regard as a Blanda Hybrid rather than a Rugosa Hybrid, is an example of the truth of the foregoing assertion. Its percentage of rugosa, however, is substantial, and it is to the rugosa element in its make-up that the fall blooming habit of the variety is due. The limited number of seedlings of Therese Bugnet raised to date suggests that the combination of good features achieved in it was due to an extremely rare and felicitous segregation, but this is no reason, of course, why the line should not be followed much further.