(1916) the Planting Of Irises by E.H. Jenkins

The Gardeners' Chronicle, p.295, December 16, 1916

The Planting of Irises.–In Mr. Dykes' criticism of the numbers of flower spikes produced by the three varieties of Iris in the experiment on March versus June planting suggested by Mr. Jenkins, he justly notes that in the case of two of the varieties, Argus and Gracchus, the figures may equally well be used as an argument against March planting, and in the case of the third, Queen of May, the figures pointed rather to something wrong with the plants chosen or other circumstances, than to any effect due to the time of planting. This is all the more likely, since Queen of May, though it apparently does flower freely in some situations, is notoriously a very uncertain flowerer. For that reason it is not a good variety to choose ; moreover, it is rather susceptible to disease. For such an experiment only regular and free-flowering varieties should be" chosen. Of the Pallidas, I have found Leonidas and Albert Victor, and, if a Red Pallida is chosen, Assaurez, the most certain and regular in flowering. In the other sections, the standard varieties Flavescens, Mme Chéreau, Perfection and Mrs. H. Darwin (the latter two are exceptionally free), Monsignori Sybil and .Tacquiniaiui (those two are less. Certain than the others, but they are representative), Gracchus, Maori King, and Innocenza flower regularly and freely every year, and are all comparatively unsusceptible to disease or adverse influences. With regard to the autumn period of rooting, Mr. Dykes states the case, I think, with undue moderation, in pointing out to Mr. Jenkins that "new main roots are pushing out from the rhizomes certainly as late as August, and often into September. ' Unmoved plants may cease rooting earlier, but with plants moved in August the rhizomes continue to put out new main roots quite to the end of September, and; sometimes in October. The chief period – when the roots are being most freely produced – is, however, in August, especially the latter part, or immediately after rain following a period of dry weather in that month. A. J. Bliss.
In his reply to my note on this subject Mr. Dykes (see p. 382) introduces the Tulip and Crocus, observing that I wish it to be believed " that the Iris behaves " like these in their rooting. Nothing, indeed, was farther from my thought: on the contrary, I regard these plants as irrelevant. That Mr. Dykes is not converted to my view of March planting is not at this juncture very material, thought it must come to this eventually unless he is prepared unreservedly to withdraw the dictum laid down by him in Irises (Present-day Gardening Series), Chap. XIV – and with which I am in full accord – " that to insure success in transplanting Irises they should be shifted in time for the main roots to go down uninjured into the soil. "At no other period than that immediately prior to the emission of these main roots" – i.e., March or thereabouts – is such work possible. Of far greater importance is the recognition and admission by Mr. Dykes that the planting of these Irises at or about flowering time, as hitherto adopted and prescribed by him, is sufficiently wrong to require "certain modifications of the rule." Unfortunately, the planting of the Iris at flower-time has during recent years been spreading like an infection, and it will be small satisfaction to unthinking gardeners and amateurs who have adopted it with little success to discover now that they have been misdirected.
Realising that " certain' modifications " are necessary, Mr. Dykes finds himself to-day in a transition stage, not quite knowing where to turn for the best planting season. That being so, I may be permitted to put my case clearly. Firstly, I place March as the best planting season of the whole year, with August-September as an excellent second. March is best because it finds the plant in a condition of comparative inactivity, together with the immediate prospect of an all-round activity and all the advantages derivable from the unchecked production of root-fibres, rhizome, and leaf development in the position where, fourteen months later, we hope to see the plant flowering. March-planting, indeed, is virtually in the same relation to the Iris as is the dormant period in bulbous plants, and the advantages of planting the latter prior to main -root production is known to all. June, or, as I may for convenience call it, the flowering period, or thereabouts, of the plant, is bad and wrong because everything – main roots, leaf growth, and rhizome – is at that time soft and immature ; the injury and check inflicted by planning at such a time is directly responsible for the non-flowering of the plants a year hence. 'Twixt June and July is but a question of degree. It was the last-named month that I first took exception to in respect of the 1913 Wisley trial, and what I then predicted as to the future conduct of the plant was fulfilled to the letter. August-September constitutes an " excellent second " planting period, because at that time leaf and rhizome are fully developed and practically mature, and, with the germ of the ensuing year's flowering already laid, division and transplanting may then be carried out with impunity. It is not correct, as Mr. Dvkes states, to say that it has been my " invariable practice for thirtv years never to transplant Irises except in early spring," and I have never hinted, much less said so. On the contrarv, I have planted them at almost all seasons of the year, and the knowledge so gained, coupled with experiments purposely conducted years ago, constitute an excellent backing to a, somewhat extended experience.

So recently, indeed, as November-December, 1915, found me planting Irises on a considerable scale in a Berkshire garden, not from choice, but because it was a part of some work then in hand. I knew, too, that if I could get the material I wanted I should be sure of a good flowering in 1916. As a matter of fact, the whole – save two or three dozen plants the product of divisions and planting in the previous July, and supplied by a specialist – flowered well. What one loses in such a case – it affects the August-September plants also, to some extent – is somewhat of vigour, stature, and fineness of bloom, things that appeal more forcibly to the specialist than the amateur.
Mr. Dykes further suggests that I have "doubtless forgotten that new main roots are pushing out from the rhizomes as late as August and September." I have not forgotten, and it is quite true. Those new main roots are, however, chiefly from the lateral branches, and not in any marked degree from the primary rhizome. They come naturally, too, at any season, with new growth and in this way confirm and strengthen my view as to March planting. Mr. Dykes further asks me to admit that ( if we move our plants in March we sacrifice the first flowering season." As I am out only for elucidating facts and not for straw-splitting, I answer: "Yes! Virtually that is so." It is not, however, an absolute fact, and is dependent on the type of specimen planted : a fully developed rhizome of the previous year flowering as surely as if planted in the previous autumn. The flowering, however, is usually but a caricature of what an Iris should be : only interesting as showing the long-suffering nature of its tribe. Two years ago, late in March, I planted some roots of Gracchus sent me in a diseased state in the previous October. For three weeks they were exposed in a warm room. For the next three months they lay absolutely exposed in the open on a little grass plot, subject to the weather, at the end of which time I decided to plant them, to see what would happen. To my surprise, every plant flowered, four flowers being the most on any spike, and 14 inches the fullest height. Moreover, they flowered representatively well the following year, and are now normal. The reason of the first flowering is clear: the rhizomes contained the embryo bud, and, despite the long exposure and hardship inflicted, the flowers appeared because of it – a remarkable tribute to the plants' powers of endurance and complete hardiness. Indeed, I have never known an Iris of the Bearded set to suffer from March planting, much less east winds. Referring to the statistics resulting from the Wisley private trial, Mr. Dykes remarks that thev may be " equally well used as an argument against my view," proceeding: by a rather ingenious process of reckoning to show it. It does not, however, dispose of the broad facts, which are these: March-planted Argus in two years gave 74 spikes. June-planted in the same period gave 35 spikes. March -planted Gracchus in two years gave 141 spikes. June-planted in the same period save 65 spikes. March -planted Queen of May in two years gave 35 spikes. June-planted in the same period gave 7 spikes. Ignoring the latter as out of all proportion to anticipated results, does Mr. Dykes wish for anything more conclusively favouring March planting than the remainder? If he does, I hope he will decide upon a like experiment in his own garden with an invitation to myself, among others, to participate and share in the information all such experiments give. E. H. Jenkins. (The debate continues with Bliss, 1917 and Sturtevant, 1917)

For more information on historic Irises visit the Historic Iris Preservation Society at

-- BobPries - 2014-06-24
Topic revision: r6 - 14 Mar 2017, af.83
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