Saxifraga x quagrata - a new binomial: hybrid of S. quadrifaria and S. x grata 'Gratoides'.

I suppose that every hybridiser who decides "to create" a new cultivar, has some definite reason or concrete idea which he would wish to achieve. My idea, which I have tried to follow, has proceeded from the fact that there is so far no Saxifraga cultivar of the Porphyrion section from the Sino-Himalayan region, with stemless yellow flowers. In fact they grow in nature in mountain localities and were described by Harry Smith (1958), but it was not possible to cultivate them, for example S. sherriffii, and neither repeated import of these plants was successful.

  • saxifraga_sirius_alfa_1Saxifraga x quagrata 'Sirius Alfa'
  • saxifraga_sirius_alfa_2Saxifraga x quagrata 'Sirius Alfa'
  • saxifraga_sirius_alfa_3Saxifraga x quagrata 'Sirius Alfa'
  • saxifraga_sirius_beta_1Saxifraga x quagrata 'Sirius Beta'

Hybridisation in the genus Saxifraga has long been of interest to growers, partly because of the fun of seeing what the result might be and partly because of the anticipation and excitement of producing a desirable new cultivar. With few exceptions, however, there has been little systematic investigation of the breeding limits of particular species across the genus as a whole. This point is important because a knowledge of the extent to which species will cross with each other can tell us a lot about their evolutionary relationships.The ability to cross or not with other species can often be used as a measure of evolutionary divergence. Thus, if two species hybridise and produce fertile offspring, we can conclude that they are probably closely related; the production of sterile offspring suggests they may be less close. The failure to produce any offspring at all, i.e. full interspecific incompatibility, may indicate a much greater divergence and a much less close relationship. I emphasise the word "may" in these statements because the correlation between reproductive isolation and our largely morphological concept of relatedness as expressed in our classifications is not perfect. Thus some species that are believed to be very closely related because they look similar may nonetheless prove to be cross-incompatible. Confused? Don't be. In a nutshell, if two species cross, they are probably closely related; if they don't, they may or may not be related.

S. x luteo-purpurea (SSaretioides x media)

Although this interesting Pyrenean hybrid was first discovered and described by the French botanist Lapeyrouse in 1801, and written about by Walter Irving in the Gardeners Chronicle in May 1908, it was not until 1915 that real interest took hold. In that year Franz Sundermann described (partially) eleven distinct forms of S. x luteopurpurea in Allgemeine Botanische Zeitschrift. Two of these were used by Farrer and Russell Prichard to produce two outstanding cultivars, namely 'Myra' and 'Cranbourne', another recent introduction, S. lilacina, being the other parent.

Growing saxifrages from seed is easier than I had ever thought it would be - I had always thought it would be almost impossible: the plants were so slow that the seed would be impossible to germinate; the seedlings, if any did appear, tiny and irremediably perverse. Kabschia saxifrages never self-seeded, any more than the silver saxifrages seemed to, so it would not be realistic expect any success. Which is why, I suppose, it took me so long to try it - that and the fact that my father, who's usually pretty good with seeds, had not got anywhere a few years ago with a packet of Thompson & Morgan's "One Hundred Saxifrages Mix'. Anyway, it turned out, when I did finally try, after about ten years of growing Kabschias, to be relatively straightforward.