Proc. and Bull. American Rose Society (1908) pp. 55-61
Essay on Hybridisation.
By Alex. Dickson, Acting Director of Alex. Dickson & Sons, Ltd.,
Royal Irish Nurseries, Newtownards, County Down.

To the Members of the American Rose Society:

It was with considerable hesitation that I consented, at the request of your Society, to write a paper upon hybridisation and cross-pollination in relation to the rose. I may say at once, it is a request that I have refused many times from similar organizations here and elsewhere, because I have always felt, and indeed still feel, it is a subject upon which it is extremely difficult to write a satisfactory paper. The subject is one which cannot possibly be dealt with satisfactorily in a paper such as the present, and the chief difficulty one has is selecting the lines upon which to write, or the point of view from which to discuss it. I will do my best to make the paper as interesting and instructive as I can within the limited scope at my disposal. I have given the subject my most careful consideration, and I am convinced that the best method of dealing with the subject in this paper is to give you is a condensed form some of the results which have accrued from the labours of my brother and myself extending over a period of almost thirty years.

I would ask those who hear this paper read, and those who may read it for themselves, to remember, that it is written by a professional rose grower, and, therefore, by one to whom the practical results, from a commercial standpoint, were of the most vital importance, and of necessity this point of view had always to be borne in mind by my brother and myself in our line of experimental inquiry; and it is from this point of view that I deal with it.

Hybridisation is a Subject of Intense Interest.

The practical application of the science opens up an infinite and even inexhaustible field of inquiry, but those of us who are professionally engaged upon this branch of horticulture must abandon, to some extent at least, the scientific aspect, in favour of the practical. With the stern realities of life facing me, I have many times—contrary to my desire—been compelled to abandon scientific lines of inquiry, as against the production of new varieties of commercial value—a situation I regretted, but could not help.

After thirty years steady and continuous work, I am inclined to the opinion that the further one pursues the subject of hybridisation, the greater field for exploration. I have often thought, whilst pursuing my work, and watching the results, that the effect was much like that produced when climbing up a steep mountain—the further one rises. the more the plains below are opened up. I will try to explain more fully as I go on exactly what I mean, and the foregoing observations are made with a view to render less keen the disappointment, which I feel will inevitably follow the reading of this paper. I am conscious that my observations will be read before, and by, men of practical experience in horticulture, and particularly in the culture or advancement of the rose, and by men keen upon the development and improvement of the rose; and I am sorry for this reason, that I can give little practical assistance to any who are desirous of entering the field of hybridisation on their own account. I may however render their disappointment less acute. The main reason why I can render little practical help is, that, when all is said and done, hybridisation is a science of pure experiment or rather chance, as I can easily show. To do this, it is only necessary for me to assume that everyone—at least everyone interested in horticulture—knows that, so far as seed bearing plants are concerned, they will re-produce their species in some shape or form—may be with some variation, or may be exactly similar. And it follows that by the fertilisation of different varieties of the same species, new varieties, or at least varieties with some distinctive feature may produced. It is a different matter, however, to reduce the chaos, which results from indiscriminate cross-fertilisation, to something like definite order—a result far beyond my ambition, or the scope of this paper, if indeed it is at all possible. All I can do in this direction, and indeed it is very little, is to give results of our labours in hybridisation.

We began work in 1879, and naturally our first operations were upon, what were considered the finest show varieties of that day. Naturally we chose parents of the choicest colours, having beauty of form, and as tar as possible, vigour of habit. The hope of course was, that the fertilisation would re-produce varieties of a different kind, with at least some of the qualities for which the parents had been selected. The results for many years were disastrous. Keen and bitter disappointment followed our experiments. We, however, perservered, always upon fixed lines, carefully recording our crosses and results, making a close and careful observation of the most important features of the offspring of the cross; and I regret to say that in the majority of instances there was nothing but dismal failure to record. I think I can safely say that the most certain result of our crosses in the early stages of our experiments was to convince us of the absolute uncertainty of what our results would be. This prevails even now, though in a lesser degree. Possibly this is one reason why rose-hybridisation is so intensely interesting. There is always and ever the element of uncertainty in it so dear to human nature. One never knows what the fertilisation of any two varieties will produce, or more correctly-how many different varieties. One seed pod containing four seeds may—and has to my knowledge—produced four seedlings absolutely distinct in every conceivable respect. Many and many a time I have seen produced from the seeds sown from one hip, half a dozen seedlings absolutely distinct in colour and form, some as single as the ordinary dog rose, and some so full in substance that it was impossible to get them to open even under glass.

A New Start.

In the early eighties, when we began to see the results of our labors, we abandoned the original basis of our experiments namely, the fertilisation of the better varieties of Hybrid Remontant or Perpetual, and began a series of cross-pollination between the Hybrid Perpetual and Teas and Austrian Briers, and then, using the results of this first cross in a systematic course of in-breeding. The main object which we had in view, was to produce varieties of roses at once vigorous in their habit, continuous in their bloom, at the same time retaining the absolute essentials of all good roses, namely, beauty of colour, perfection of form, and delicacy of perfume. It was of course a great ambition, and how we have succeeded we must leave the world to judge. Broadly, I would say that such success as has attended our labours, is due far more to the careful selection than to any defined plan of fertilisation. As a broad basis of our experiments, we took as parents such varieties as appeared to us to embody the chief elements of our ideal, and worked steadily from these. We had of course to experiment upon a very extensive scale, and my point will be readily appreciated, when I say, that we were only able to retain for use, either for further fertilisation or for commerce, about 5 per cent. of the seedlings raised. To appreciate the labour this entails upon the hybridiser one must follow the rose from the hip until it reaches maturity. In hybridisation, carried out upon a systematic plan such as ours, it means that the plants with which we are working, have to be specially selected, planted, and grown, and the blooms fertilised. There is then the period required to ripen the hip, (and in Ireland this takes considerable time, owing to the cold and dampness of our climate.) Then comes the sowing of the seed, and the attention and care during the period of germination. In this respect, it is interesting to note the wide differences in the period of germination in the different cases. In some instances, the seed will germinate in two or three months, and in others I have known it to lie dormant from twelve to fifteen months. (I have never been able to give any reason why this should be so, and particularly why there should be marked differences in the periods of germination in seeds. taken from the same hip, yet there is very frequently a marked difference.) To continue on the point I am making, it takes anywhere from three to six months according to the vigour of the plant, to bring it to such amount of growth, as will enable us to bud it for the purpose of testing outside. Then, when it is budded of course it takes a full year to bring the plant to maturity. Here again, one has to face uncertainties, and to be very careful about forming a judgment, as experience has proved time and again, that in the early stages of culture some varieties have displayed the greatest shyness in flowering, and yet after a few years cultivation, have taken their places in the front rank, as perfect garden roses, blooming with the greatest freedom. Each year we are compelled to make a very close selection, and to discard every seedling which does not suggest some improvement in, at least, one or two of the essential elements of the perfect rose, otherwise we would of course have been flooded out with varieties, which would have been of no practical value to us, or indeed to the rose world at large.

System or Plan.

The system we ultimately adopted was hybridisation in the first instance between hybrid perpetual and teas, and then inbreeding from their offspring, upon the following lines. We made four distinct crosses. We took a seedling of our own, which gave some evidence of possessing at least some of the qualities aimed at, and, in the first instance, this seedling was crossed with the male parent; secondly, the seedling crossed with the female parent: thirdly, the male parent crossed with the seedling: fourthly the female parent crossed with the seedling. As soon as we were able to form an opinion of the results of this interbreeding, we again made a selection of those most closely approaching our ideal, again in-breeding, but with this difference, that we only made use of a limited number of parents, but in almost every instance making a double cross. For example if we made a seedling with, say, Marie Van Houtte as the male parent, then during that season, we reversed the cross, making Marie Van Houtte the seed bearing parent, and the seedling the male parent. We always had relays of plants prepared in duplicate for this purpose, and we carefully and methodically registered each experiment, thus carrying on our work in a systematic manner, the system of selection of course always playing the most prominent part in the results. From practical experience, we were able to ascertain which varieties, or rather types, gave us the beat results, and we were, therefore, able to a considerable extent to lessen the waste, and to reduce our methods to a system containing at least some elements of certainty. We of course have made use of varieties of other raisers, where we have been struck by any special feature which it contained, which was in our opinion an advance upon anything in commerce. The result of our labours has been, to produce, what la admittedly an absolutely distinct class, it not family, of roses known as the "Alex. Dickson type." We of course claim that the types of roses we have introduced have made a great advance on those previously in commerce. We aimed at producing a type having vigour of growth, freedom and continuity of bloom, the flowers full and perfectly formed, with unusually, long petals, at the same time, growing on bushes, the foliage of which is luxurious and handsome. How far the varieties we have sent out have done what we claim for them, you must judge.

In our experiments and in struggling with the qualities we have indicated, we felt convinced that La France would prove one of the most useful parents we could possible have, if we could succeed in making it produce seed. It was of course the opinion of most hybridisers that La France was sterile, and with this opinion we were for a long time inclined to agree, and indeed the best that could be said for it is this, that there is just the possibility that it may be fertilized.

A Fine Rose.

Out of many hundreds of crosses with this rose, only in one single instance did we succeed in making it produce seed, but we feel that the labour we spent was amply repaid, as the ultimate result of it was the introduction of Mrs. W. J. Grant, known to you as Belle Siebrecht, in our opinion one of the finest roses in cultivation, at least from the Britishers' standpoint. In addition to this, we have always found from practical experience, the roses descended from this particular cross have always impressed their offspring with some at least of the more prominent qualities of the parents, and it was pursuing this particular line of breeding that enabled us to produce varieties, which from a British standpoint are ideal exhibition flowers, and at the same time the plants are floriferous and of excellent constitution. In this group we might mention Killarney, Mrs. Edward Mawley, Bessie Brown, Liberty, Lady Moyra Beauclerc, Lady Ashton, Mrs. David McKee, Dean Hole, Countess of Derby, Betty, Mrs. G. W. Kershaw, and last but not least Mildred Grant and William Shean, two of the finest exhibition roses at present in cultivation in Great Britain. Mildred Grant resulted from a seedling between Niphetos and Madame Willermoz in the first instance, crossed with a seedling of our own, which is not in commerce, and the system of which this is an instance applies pretty generally to all the better classes of roses introduced by us.

Patient Work Rewarded.

After many years of continuous experiment on various lines we have at last been able to produce what has long been sought for, namely, a yellow Tea of good size and colour with the vigour and hardiness of the Hybrid Perpetual. I refer to the rose Harry Kirk, which is now being grown by most of you, and you will shortly be able to judge whether it fulfills the promises we have made on its behalf. I think you will not be disappointed.

It is interesting to note, in relation to the La France cross, that the same inclination to sterility is apparent in the rose Augustine Guinnoisseau sport from La France. Out of hundreds of experiments we have not succeeded in getting a single seed pod from this variety.

The only other point of practical importance, which occurs to me, is the fact that in our early experiments, when we had in view the object of producing varieties which would give a greater continuity of bloom, we used in our efforts Rosa lndica, and after a considerable amount of labour, we succeeded in impressing this much valued quality on some of its offspring which are now in commerce.

In a general way we found it very difficult, and indeed impossible to place the smallest dependence upon the presumption that Hybrid Perpetuals would impart to their offspring anything of their own colour, and in a general way we may say that after much experience the chief varieties we use and use with the best results for the purpose of getting blends are the Hybrid Perpetuals, Horace Vernet, Charles Lefevre, General Jacqueminot, and also Austrian Briars, Persian Yellow and Harissonii.

From what I have said, you will readily appreciate the fact, that it would be wholly impossible, and indeed, I think a waste of your time and mine, to give in detail the results of thirty years hybridising, and I have done my best to make clear the general lines upon which our work has been conducted, from which it will be readily inferred, that the element of chance must always play a prominent part, and I might aptly use the well known quotation from Pope

"All nature is but art, unknown to thee;
All chance, direction, which thou can'st not see."

And I ask of you, as may desire to enter for yourselves upon this interesting field of experiment, to go forward with confidence

"Knowing that nature never did betray
The heart that loved her."