(1917) Notes on Irises; Regelia Irises, some Juno Irises by Dykes
Gardeners' Chronicle p.249, June 23, 1917
NOTES ON IRISES.
May I give a warning to those who grow these beautiful Irises? It is that the rhizomes should not be lifted until the root-fibres are fully developed. In early June it will probably be found that the foliage is beginning to show signs of turning yellow, and that the tips of the new growths. at the ends of the running stolons are showing through the ground. Until last year I always took this to mean that growth was mature and hastened to lift my plants before the main root-fibres sent out their lateral shoots. I was, however, always disappointed to find that the roots died away before planting time came in October, and that flowers were few in the following summer. Last year I left my plants in the ground until the middle of July, by which time growth was much more mature. The result was that the rhizomes and roots were in far better condition in October, and this season the plants flowered better than ever.
SOME JUNO IRISES.
The Juno section of Irises is by no means a homogeneous group. There are at least two main groups, those with flowers of which the haft of the fall bears large wings which arch over and clasp the style branch, and those of which the haft of the fall is strap-shaped and wingless. The seeds of the species of the two groups are very different, but our knowledge of some of the rarer species is still so scanty that it is impossible to say with certainty into how many sub-divisions these two main groups naturally fall.
It would be interesting if some geologist could tell us whether in the hills of Asia Minor the soil is a stiff clay, or at any rate that heavy red loam which is found in the limestone districts of southern Europe, and which seems to be extraordinarily fertile, and also whether there are not large tracts of sandy soil in Turkestan. These theories are deduced from the behaviour of various plants in this sandy soil in Surrey, and it would be interesting to know whether they are in accordance with facts. In any case, the fact remains that the Persica group of Irises dies out here, such Tulips as pulchella and polychroma are none too happy, and Fritillaria aurea refuses to live, while Iris bucharica grows like a weed, Tulips such as Kaufmanniana arc difficult to eradicate, and Fritillaria pallidiflora grows 2 feet high, with six or seven flowers on each stem. Of these plants, the former are all natives of Asia Minor, while the latter come from Turkestan.
Experience has therefore led me to abandon the Western Junos, and to concentrate on the Turkestan species, which have well repaid my interest in them. Last summer I lifted all my bulbs of Iris Rosenbachiana, and my belief was confirmed that there are either two species or two very different local forms concealed under this name. Dr. Fedtschenko has alluded to an Iris baldshuanica in the Journale Russe de Botanique
1909, p. 77, but as he only separates it from I. Rosenbachiana by saying that the flowers are yellow, it is difficult to be certain with what plant he was dealing. I would suggest, however, that the true Rosenbachiana is The early flowering form with bright orange pollen, the thick fleshy roots on the dormant bulb taper gradually and are of a pale yellowish- brown. Here I have only one colour varietv of this form, and the flowers have falls marked with a bright crimson-purple on a white ground. The later form, which is probably Fedtschenko's baldshuanica, is very variable in the colour of its flowers, and has given me one or two seedlings of a pale creamy-yellow marked with brown-purple. This form has white pollen, and the roots taper much more abruptly than do those of the true Rosenbachiana, and are of a whiter colour. I found when dealing with large numbers of bulbs that I could separate them into the two species by the colour and formation of the roots.
Perhaps the most striking and certainly the most vigorous of all the Juno Irises is I. bucharica, with white and yellow flowers. Here it has combined with the yellow I. orchioides and given me wholly yellow forms, with the vigour and size of bucharica. One chance seedling of bucharica has come wholly white except for a pale yellow crest, and in others the deep yellow of the type is replaced by a pale, delicate lemon-yellow, which gives a beautiful effect. I. bucharica also crosses readily with I. warleyensis, and many different seedlings have recently been in flower here. The style branches and the standards are usually tinged with blue, and the blue of warleyensis contends with the yellow of bucharica to produce much variety in the markings of the falls. Sometimes these are yellow with a greenish tinge at the edge ; sometimes the blue-purple only appears as blotches on the yellow, and sometimes there is little trace of the influence of warleyensis on the falls at all.
Iris warleyensis grows well here, but never with the vigour of bucharica. It has also given me a variety of seedlings, including a white form which retains the orange-coloured crest of the type, and pale yellow forms which also retain this feature.
Iris orchioides is rich in colour, but the flowers are small and insignificant in comparison with those of I. bucharica. Seedlings vary a good deal, some having conspicuous bright green markings on the golden ground; some are of a pale sulphur-yellow, while others are wholly white or white with a yellow crest.
My failure to keep Tubergeniana and Willmottiana. both of which come from the neighbourhood of Tashkent, in Turkestan, and have winged falls, makes me wonder whether (there is not in that district a region, of the heavy soil in which this kind of Juno Iris appears to revel. Yet the various crosses between sindjarensis and forms of pereica, which Van Tubergen has raised at Haarlem, presumably in the sandy soil of the bulb garden, dwindle away here.
The lifting of a number of bulbs of Juno Irises is most trying to the temper, even in the lightest of sand. In heavy soil, baked hard in summer, it must be so disheartening that no gardener except the most callous could persevere with it. The slightest jerk or twist snaps the fleshy, brittle roots or detaches them bodily from the base of the bulb. It is true that clusters of roots thus detached do develop buds in the course of time, but I have yet to find that these ever develop into vigorous bulbs.
I. bucharica seeds here abundantly, and seedlings are easily raised in pots sunk to the rim in the open. The seeds must be sown soon after they ripen, or germination will be unsatisfactory. At the end of the first summer the small bulbs may either be left a second year in the same pots, if the latter are large and the soil rich, or sifted out and planted in September in beds in which they will flower two or three years later.
W. R. Dykes, Charterhouse, Godalming.
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