IRISES OF THE FUTURE. W.R.Dykes

THE GARDENERS' CHRONICLE.
May 28th, 1921.

IRISES OF THE FUTURE.

W. R. Dykes

IT is never easy to prophesy correctly, even if successful prophecy is little more than intelligent anticipation. The following notes, therefore, are intended less as an indication of the future than as possible suggestions.

Among the early bulbous Irises there seems little hope of new developments, unless we can hold in check the fungous disease which plays such havoc among the bulbs. If we could overcome and eradicate this, there would be no end to the delightful series of beautiful hybrids which might be raised by crossing the richly coloured, velvety-petalled I. Bakeriana with the other species. The yellow I. Danfordiae might also be used to give us entirely new forms.

The Juno species seem to suffer from an undeserved neglect, for there are few finer garden sights in April than a large mass of the glistening, sturdy foliage of I. bucharica, closely set with the large white and yellow flowers; while the endless variety of colouring to be found among seedlings of the gorgeous I. Rosenbachiana well repays the patience which is needed during the three or four years that the bulbs require to grow from seed to flowering size. The later bulbous Irises, comprising I. Xiphium, the Spanish Iris and the kindred species, seem to have fallen under a cloud, from which they will hardly emerge until some remedy is found for eel-worm in the soil, for this pest appears to be as fatal to Spanish Irises as it is to the Narcissus. If this can be overcome, the multiplication of the florists' varieties, both of the Spanish and of the Dutch Iris, will go on; but we cannot expect much from their combination with any of the allied wild species, though these are distinct enough in themselves. They do not seem to combine well either with one another or with I. Xiphium. Thus I. filitolia, when hybridised, loses its magnificent red- purple colour ; I. Boissieri has the long hairs of its beard shorn down to half their length; while the clear golden yellow of I. juncea becomes dull and streaky.

Of Oncoyclus and Regelia Irises I am distinctly more hopeful than there seemed any justification for being a few years ago. Experience seems to show that these must all be dug up annually about the middle of July. The rhizomes may then be left lying out on the ground for a few days, provided that the sun is not too incessantly brilliant and scorching. They should then be trimmed of their leaves and be stored away, preferably in perfectly dry sand, in a well-ventilated, dry place, until the first week in October. The rhizomes and the roots should, with this treatment, remain firm and be ready to start into root growth as soon as they are replanted in rich, well- drained soil. At one time it used to be thought that the soil must first be beaten and trodden down until it was almost as hard as a rock, but this seems unnecessary, in view of the way in which these Irises flourish in the loose sand of Haarlem and in the drier, but equally light, Surrey sands.

To my mind, the fault of the Regelia-cyclus hybrids that are already in commerce is that they are nearly all of them mere colour variations of the same type of flower. When we remember, however, how utterly different I.paradoxa is from I. susiana and from I. iberica, and how each of these latter differ from the aptly named I. acutiloba and from the rounded, self-coloured flowers of the purple I. Mariae and its yellow counterpart, I. urmiensis, I cannot help feeling that crosses with these species might give us new types. Evidence to confirm this exists in the pleasing results that have resulted from crossing I. acutiloba and I. Sari with I. Korolkowi. The former gives very floriferous hybrids with the extended falls of acutiloba and the prominent veining of Korolkowi, while the latter retains the shape of I. Sari and something of the colouring that won for that species the name of the Wolf Iris, I. lupina.
No hybrids have yet appeared of I. Hoogiana, the last discovered and most astonishing member of the Regelia section. Its unveined, self-coloured flowers of pale or dark blue- purple are so beautiful that it seems almost sacrilege to attempt to hybridise into them the veinings and dottings of the other Regelia and Oncocyclus species, with which there would probably be no difficulty in making crosses.
Nothing has, so far, been said about the great class of Pogoniris or bearded Irises, which to so many comprises practically all the Irises that they know. Here the tendency is to aim at increased stature and a more widely branching habit in the inflorescence, qualities which are obtained by using as parents I. trojana and other giant species, such as I. mesopotamica and I. cypriana, which have now become more widely distributed. Whether we should aim at self-colours or at variegation in the flowers is a matter of personal taste and it is devoutly to be hoped that no self- constituted body of florists will attempt to lay down strict canons on this or on similar points and then try to ensure that all our Irises should conform to these canons.
For garden ornament it is hard to find anything more decorative than self-coloured pallidas, which can be obtained in a long series of shades from a deep blue-purple to a pale pink. If pallidas are, as a whole, later than the so-called I. germanica, it is easy to obtain an early race by crossing I. pallida with I. Albertii, from Turkestan. The characteristic veining on the falls, which ends so abruptly and which is typical of the species, is not sufficiently prominent, except at close quarters, to spoil the effect of self-coloured flowers. At the other end of the season something might be done towards prolonging it by using the late-flowering Black Prince. Seedlings of this tend to retain the late-flowering habit, and, as there is a large dose of I. variegata blood in Black Prince, forms with yellow standards are sure to appear among them. It remains for the hybridiser to get rid of the stunted stem, the crowded inflorescence, and the ugly form of the flowers, with their erect, widely separated standards.

Among the Evansias something good might come from the crossing of I. Wattii, which does so well when planted out in a cool house. It ought to cross with I. japonica and possibly also with I. tectorum and I. Milesii, if these two could be forced into flower early enough. I. tectorum and I. Milesii seem themselves to be so closely related that it is surprising that all attempts to cross-fertilise them have hitherto ended in failure, though a combination of the large flowers of I. tectorum with the tall stem and sturdy foliage of I. Milesii ought to make a most effective garden plant.

Among the Apogons or beardless species there is still scope for much work in hybridisation. The members of the various groups of obviously closely related species hybridise fairly readily with one another, and it is also possible to cross members of different groups with one another. For instance, the Californian I. tenax will cross with the Chinese I. Wilsonii, and the hybrid bears curiously speckled, dull purplish flowers with a yellow ground. I. Douglasiana crossed with the Himalayan I. Clarkei gives a mottled, pinkish flower of no great merit, but, when crossed with the Chinese I. chrysographes, gives a beautiful flower of a crushed strawberry colour, with gold veining on the falls.
Those who will take the trouble to raise seedlings should turn their attention to the group of Californian species, of which it seems true in many cases that no two individual plants produce flowers of the same shade of colour. The variety to be found among seedlings of I. Douglasiana, I. tenax, and I. macrosiphon is endless, and, as the plants flower in two years from seed, no one need hesitate to embark upon their cultivation. The seeds should be sown in pots or pans, and the young plants are best grown on quickly under glass, so that they are large enough to be planted out in the open in their permanent positions in May if possible, or, at any rate, before midsummer. They should then grow rapidly and develop before the autumn into plants of sufficient strength to pass safely through the winter.

The Sibirica group has lately been extended by the new introductions from China, and all its members seem to hybridise readily with one another. Much may be done with the older and well-known species, I. sibirica and I. orientalis, for the large flowers and brilliant colouring of the latter can be readily combined with the tall stature and floriferous habit of the former, while 'the crossing of the white with the blue forms of either species will give seedlings a nearer approach to a true sky-blue than is found in any other Iris. The yellow Chinese I. Wilsonii will give a yellow ground to I. sibirica and to I. Delavayi, and the combination is particularly pleasing in the latter case.

Two of our native species, I. Pseudacorus and I. foetidissima, do not seem to lend themselves at all readily to hybridisation with others. I. Pseudacorus seems to reproduce itself with whatever pollen the flowers are fertilised, and nothing ,seems able to fertilise I. foetidissima except its own pollen. It is true that there exists a plant which appears to be a hybrid between I. Pseudacorus and its closest ally, namely, the American I. versicolor, but no record exists of the origin of the hybrid. Its sterility is some indication of its hybrid origin and its intermediate position between the two above-named species suggests that they were its parents.

Hybridisation is a fascinating pursuit, and enough has already perhaps been said to show that much remains still to be done among Irises, especially when we remember that crosses that have often been tried in vain may at length prove successful.

W. R. Dykes.

The above article has also been published in the book 'Dykes on Irises' compiled and edited by George Dillistone, a reprint of the contributions of the late W. R. Dykes to various journals and periodicals during the last twenty years of his life.

Reproduction in whole or in part of this post, its opinions or its images without the expressed written permission of Terry Johnson is strictly prohibited.
Photo credit and copyright Terry Johnson and Heritage Irises ©.

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Iris Species X HOLDEN CLOUGH

It's thanks to the bee's and the chance find and intrigue of a plantsman. Its pedigree may never be really known, but my what a beautiful exotic looking flower that originated from England no less. Named after the nursery where the plant originated and is  still sold today at the Holden Clough Nursery, Bolton-by-Bowland, in Lancashire. Considered to be a 'Water or Bog Iris' but so long as you take care not to let the plant dry out in the summer season until the plant is established it will grow well in the regular garden, and I find it does appreciate a bit of midday dappled shade.

The Iris Yearbook (BIS), 1971, Holden Clough - An Unusual Iris Hybrid. Donald M. Patton.
Walking around a nursery in Yorkshire we noticed a short row of Iris whose foliage was unfamiliar but although it was not yet in Bloom and the staff of the nursery, in the absence of the proprietor, could give no information about it, a plant was purchased and taken home. When early in June the first flower opened it was seen to be one that did not match any known species or hybrid. There was however, some resemblance to I. pseudacorus. On making further enquiries at the nursery it was established that the plant was an odd one out of a batch of seedlings raised from a pod of seed taken from a plant of I.chrysographes. All the other seedlings appear to be similar to I.chrysographes.
A plant was given to Dr Jack Ellis who made a chromosome count and found that 2n=37. If we accept that the plant came from I.chrysographes seed then since the chromosome number of that species is 40 that of the other parent must be 34 and this fits I. pseudacorus. It appears that I. pseudacorus was not actually growing the nursery where the hybrid originated but it has been known to grow wild nearby and it is not unlikely that bees carried the pollen to the nursery. Pending closer examination of the chromosomes, therefore we feel satisfied that the hybrid is I.chrysographes X I. pseudacorus although this is a cross not previously recorded.
Apart from its botanical interest the new hybrid is quite an attractive garden plant with a very unusual flower colour. It is, therefore been registered under the name of 'Holden Clough' to commemorate the nursery where it originated and the plants will be obtainable from the nursery of Mr Linnegar.
The plant is less vigourous than I. pseudacorus but has many similarities including the leaves which have a distinct rib and are about 24 inches high. The flower is yellow, closely veined purple and the general effect is brown. The falls are flaring and have a bright yellow spot pattern created by a deepening of the veining around the spot area. The standards are small and stand at an angle of 45°. The style arms are cream and the crests purple edged yellow. The stems are well branched and carry the flowers to a height of 26 inches. Like pseudacorus the rhizomes are hard and red fleshed. The roots are strong and the plant appears happy in a damp spot. It seems to be an excellent grower and very free flowering. Dr Ellis reports that the pollen is sterile but the seed pods persist on the flower stems and there appear to be a few seeds although we do not expect that they are viable. The seed pod is triangular, dark green and not unlike that of I. pseudacorus.

Bulletin of the American Iris Society, Summer 1978, Number 230.
At the Species Level ; Those Wide-Cross Hybrids-Hooray!
In scanning lists of wide crosses and presumed hybrids raised in the past, a species that frequently appears is I. pseudacorus. Although we have no proof that some of the old reports were of authentic hybrids (and plants are no longer around for chromosome study), there can be little doubt now that this species is an important tool to future apogon iris breeding. In Japan, after generations of attempts, have been produced yellow Hana-shobu hybrids yellow Japanese irises-while in Britain the brown water-flag HOLDEN CLOUGH is thought to have been sired by I. pseudacorus on I. chrysographes (one of the Himalayan Sibiricae).

The Iris Yearbook (BIS), 1978,The Hugh Miller Trophy
This trophy restricted to non-bearded irises, was awarded in 1978 to the inter-species hybrid 'Holden Clough' selected and Registered in 1971 by the late Donald Patton. The flowers are yellow, marked purple, giving a brownish effect. It was found in a nursery in a row of seedlings from I.chrysographes and the pollen parent is believed to be I. pseudacorus. It was given an A.M. by the Joint Iris Committee in 1973, and the A.G.C.by the B.I.S. in 1976.

 Bulletin of the American Iris Society, Fall 1978, Number 231.
A Shiny Yellow Seed on 'Holden Clough', Roy Davidson, Washington.
In my work with iris species I have followed not only the species themselves as new and better forms were found and introduced, but also the hybrids, those not conforming to anyone species, no matter where they originated. Thus I was most intrigued with the idea of a brown water iris when I read in the British Iris Society YEAR BOOK 1971 of Mr. Patton's finding it in a nursery row of supposed Iris chrysographes. Later it was proposed that somehow pollen of I. pseudacorus had been responsible for those aberrant plants in the row. Dr. Ellis made a chromosome Count, reported that the chromosome component would allow that premise, and it went on the record that the plants were hybrids of I. chrysographes and pseudacorus. There were, however, some discrepancies to that theory. For example, how could two such thin-leaved, deciduous species have
given rise to a hybrid having firm, rigid leaves that would stand up to considerable freezing?
Melrose Gardens had imported this hybrid HOLDEN CLOUGH into California, and a piece was planted in my Washington state garden in autumn of 1976; most surprisingly it flowered the following spring, although in my absence. The stalk was there, however, on my return, and it stood up firmly through the winter in a manner that no I. pseudacorus nor any other water-loving species can maintain.
It has been Ben Hager's idea that somehow I. virginica was possibly responsible for HOLDEN CLOUGH, mainly as an explanation of the firmly evergreen foliage. However, the stalk of that species is among the softest of all, often collapsing in a mush before the capsules are open.
This last iris season saw another stalk on my HOLDEN CLOUGH plant which by then had increased to three. The stalk reached twenty-eight inches high, and a total of ten flowers were given in a long season of bloom, the flowers held just above the foliage which had elongated to thirty inches. In full sun the leaves had a good rich green color, further enhanced by a nice polish to the surface.
Just across the path from HOLDEN CLOUGH grows a well established clump of I. foetidissima which was on the property when I came. I was struck by the similarity of the two plants, and although I did not have flowers simultaneously for comparison they seem, in memory, to have been decidedly alike except for color. In the process of comparing the two I had cut the stalk of HOLDEN CLOUGH, and a few days later Phil Edinger discovered that one of the shrivelling pods had an unmistakably hard, round seed in it. Right away the stalk was put into a bottle of water, where it stood for a week. Finally the strain of waiting became too great (and it was evident anyway that the entire stalk was beginning to dry up) so the seed was removed.
In two ways it was a very curious seed. First, it had a distinctly shiny yellow seed coat, and that had been hoped for since it would give almost certain evidence that HOLDEN CLOUGH had been a chance development from I. foetidissima. A pod of I. foetidissima, opened for comparison, revealed that at the same approximate stage of development its seeds were about the same appearance and color, though they would redden up later. The second odd detail of this seed was its shape: rather than round and bead like, it was sort of bi-lobed, almost as though two ovules had become fused (or had not become fully separated? Ed.). This seed is of course planted, and with high hopes; except for shape it was quite plump and normal appearing. What can we hope for, beyond germination and growth? Should it in time produce flowers, will they reveal the answer to the parent's ancestry? The label in the pot reads simply HOLDEN CLOUGH F 2" • • • Editor's note: The chromosome count of HOLDEN CLOUGH made by Dr. Ellis established the possibility that the parents could have been 40-chromosome I. chrysographes and 34-chromosome I. pseudacorus. Interestingly, 40 chromosomes also is the count for I foetidissima.

Melrose Gardens, Stockton, California. The Connoisseurs Catalog 1981
Water Iris.
HOLDEN CLOUGH Unusual hybrid between iris pseudacorus X ?. Rampant, evergreen plants produce tall, branched stems and smallish flowers gold ground veined brown maroon...........................................$4.00

Tempo Two, Pearcedale, Victoria, Australia. Iris, Daylilies, Hosta Catalogue  1994-1995
Iris Species suitable for water or boggy conditions.
IRIS HOLDEN CLOUGH (Patton UK) L 26"
Chrysographes hybrid, maybe I. pseudacorus X ? Flower are an intriguing brown with deeper veining. Not showy but of interest for floral art and will grow in water conditions as well as normal beds..................................... $6.00

IRISES, A Gardener's Encyclopedia, Claire Austin.
HOLDEN CLOUGH D. Patton, , R. 1971. Change of classification and description to: Wide apogon hybrid of unknown origin and totally unlike I. chrysographes with which it was found growing. Resembles both I. pseudacorus and I. foetidissima and in many respects seems intermediate between the two. Evergreen foliage in warmer climates. Occasionally sets seed with colored flesh outer seedcoat. Flesh of rhizome is pinkish as in I. pseudacorus. Chromosome count 2n=37 made by Ellis; Previous checklist entry below.

The Garden, June 2013. Roy Lancaster visits... Holden Clough Nursery.
'Named after the nursery'.
A plant in cultivation that originated from this nursery in the days of Richard Milne-Redhead is Iris Holden Clough which has been considered by some to be a curious form of the British  native flag ( I.pseudacorus) differing in the purplish brown heavy veining of its yellow flowers. To my eye at least, this gives them a somewhat muddy appearance from a distance. John's (Foley) description of it as a 'Marmite plant' (you either love it or hate it) is most apt. It is definitely a plant for collectors with its curious flowers and winter green leaves. It is also versatile in its growing requirements coping with both moist and average garden soils.

AIS Checklist 1979
HOLDEN CLOUGH    (D. Patton, R. 1971).  Chrysographes hybrid 26" (66 cm) L.     Yellow, veined purple, giving a rich brown appearance; form resembles I. pseudacorus. I. chrysographes X I. pseudacorus., S. Linnegar 1971.

As always clicking on the above image will take you to the larger, higher resolution version. Reproduction in whole or in part of this post, its opinions or its images without the expressed written permission of Terry Johnson is strictly prohibited. Photo credit and copyright Terry Johnson and Heritage Irises ©.

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