(1920) The Origen Of the Dutch Irises by Van Tubergen Jr.
The Garden p.594, December 4, 1920
THE ORIGIN OF DUTCH IRISES
Perhaps as the originator of the race of Dutch Irises you will kindly allow me to state a few facts about their raising. The difference of opinions as expressed about their origin in the Rev. J. Jacob's article and in that of Mr. W. R. Dykes in your columns is, I think, principally due to the fact that the former expert is considering them from a practical grower's standpoint, while Mr. Dykes lays most weight on botanical details. When Mr. Dykes asserts that the yellow and white flowered Iris lusitanica from Portugal and the very distinct early-flowering purple-coloured variety of Iris Xiphium, I. X. praecox, long grown in Dutch gardens under the erroneous name of Iris filifolia, are both forms of I. Xiphium, no one will contradict him from a theoretical point of view ; but regarded from the gardener's side, there is a very great difference indeed, as both the former flower quite a fortnight earlier than the ordinary Xiphiums (Spanish Irises), while the flowers also are of greater size. These two all important points first suggested the idea to me to make crosses between them, little thinking that almost from the very first the intermarrying of these two forms would at once yield a quite remarkable number of meritorious varieties, none revealing the much later flowering character of the ordinary Spanish Irises. I also used Iris tingitana later on, but as this is, at least here, a very sparse-flowered Iris of doubted hardiness, only one or two varieties were raised, and kept out of this combination, one of them being the variety David Bles, cited by the Rev. Jacob on page 538 of The Garden, October 30. The latter varieties are easily recognisable by their greyish broad foliage and also from the botanical detail of their having inherited the long tube found in the flowers of I. tingitana. It is quite as the Rev. J. Jacob who from the first has always been much interested in the Dutch Irises, and for which he suggested the name says, that later on, in the further development of this strain, the ordinary Spanish Iris never came in. Obviously from a grower's point of view this would have been a serious mistake, the aim being from the very first to have a strain flowering decidedly earlier than the Spanish Irises. Had I also used the latter, the inevitable result would have been to retard the flowering by their influence. It is here that I am entirely at variance with Mr. Dykes, where he quite erroneously states that one can easily obtain the Dutch Irises by simply crossing the Iris filifolia of Dutch gardens with the Spanish Irises. If one does so, one will get, to my mind, the somewhat objectionable race of Irises flowering midway between the Dutch and Spanish strains, with flowers smaller than those of the true Dutch race, also possessing, as quite naturally might be expected, the peculiar smell and the unmistakable look of and affinity to their Spanish ancestors. It is obvious that where there exist dozens of very distinct and beautiful varieties of Spanish Irises, and also quite a considerable number of the so much earlier flowering Dutch race, the second flowers of which are fading just when the earliest varieties of their Spanish cousins begin to open, there is in reality no room for, and no need of, another intermediate strain.
While writing on early- flowering Xiphium Irises I cannot refrain from speaking admiringly of the varieties lately raised in Holland out of the Iris filifolia (praecox) of Dutch gardens, which have entirely retained not only the early-flowering habit, but also the very elegant form of the flowers of that well marked variety ; in fact, the more one sees of this Iris and its seedling forms, the more one feels inclined to regard it as a species, just as tingitana, lusitanica and similar are also classed and have been described as such. Where possibly may be the wild habitat of this Iris, and when has it been introduced to Dutch gardens ? I am also wondering whether at any time intentional or chance crosses will reveal the origin of the Spanish Irises, and especially where those beautiful deep bronze varieties, such as Reconnaissance and Thunderbolt, come from. It is now about twenty-five years ago that I first flowered the hybrids between Iris Xiphium filifolia (praecox) and Iris lusitanica, and I have ever since intercrossed the best varieties which cropped up ; but, although I raised many tens of thousands of plants, I never up to now obtained a real deep bronzy variety in this strain. I know it is suggested that those deep bronzy orange Spanish Irises came from a reputed wild growing deep-coloured form of Iris lusitanica, but every single plant one raises of I. lusitanica will retain its early flowering character; whereas all bronzy varieties of the Spanish Irises are among the very latest flowered of their race. C. G. van Tubergen, jun.
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