Frederick William Burbidge
At the last meeting of the Royal Horticultural Society, held on November 11th, it was stated that Mr. Maule, of Bristol, had succeeded in grafting Solanum nigrum and S. Dulcamara — common garden weeds, on to the stem of a Potato, his object being to infuse fresh vigour into the constitution of the variety of Potato acted upon, and so enable it to resist disease. We can scarcely hope for any practical and desirable result from such a union, as both the plants are poisonous species, yet the subject is of considerable interest, and it is one of those experiments which, without being of much practical value, still set one thinking, and are highly suggestive. In the "Gardeners' and Land Stewards Journal," 1847 (p. 85), is given a short account of an experiment in which a Tomato scion was grafted upon the stem of a Potato, and the scion developed its fruit and the stock formed tubers. We are not told precisely how the stock and scion behaved under the circumstances, but this experiment seems better worth repeating, since the results cannot but be highly interesting, from whatever point of view they are considered.
Among all the authors who have written on grafting, from Parkinson downwards, I find none more explicit than R. A. Austen, who, in his "Treatise on Fruit Trees" (1755) p. 48, writes as follows:— "And in setting the grafts into the cleft, observe this for a most speciall rule, to joyne the inner side of the barke of the graft to the inner side of the barke of the stocke, that the sap may more easily come out of the stock into the graft to feed it, for the main current of the sap is betweene the bark and the wood. And regard not the custom of many grafters, in setting the outsides even and smooth, not considering the insides, their success is according to their skill for the most part. We know the bark of a big stock is much thicker than the bark of a slender graft, and if the outsides be smooth, and even the insides must needs be uneven."
When and where did double grafting originate? I believe it was first secretly practised by the old German gardeners about three centuries ago. Parkinson (1625) recommends that the Red Roman Nectarine should be budded on an Apricot shoot that has previously been worked on a Plum stock, and Austen, in the above cited work (p. 57), says, "But I hold it best to inoculate the Red Roman Nectarine upon the branch of an Aprecock, which before hath been inoculated upon a good Plum stock, that it may give not only a larger but a finer nourishment than ordinary Plum stocks can doe."
Even leaves may be grafted, and in the "Revue Horticole,"1866, a curious case is mentioned where MM. Thibaut and Keteleer succeeded in grafting an Orange leaf which had been taken off and struck as a cutting, the result being that the leaf and its petiole acquired a woody and persistent character. The leaves of Pachyphyllum bracteosum may also be made to serve as stocks for other Crassulaceous plants, and further experiments will, doubtless, greatly augment our knowledge of such cases.
During the past year Mr. Smith, of Worcester, exhibited a fine golden-leaved Laburnum at South Kensington, and this, which had first been detected on a green-leaved Laburnum as a sport, had been multiplied by budding on green-leaved seedling stocks. Some time after they had been budded golden-variegated branches were produced on the stock below the point of union, and even suckers from the root so variegated were produced. Similar instances have been often observed from the year 1771, downwards, in the case of variegated Jasmine, Abutilon, and Passion-flowers, when budded, and are highly interesting to students of vegetable life.
About 1873, M. Zenone Zen sent a paper to the Royal Institution at Venice, in which he stated that, after much study and many experiments, he had discovered a secret by which different varieties of Roses might be produced by a peculiar system of budding, and in order to test his assertions, two well known Italian botanists were appointed by the Institute to report on M. Zen's method, and in their presence, as we understand, buds were taken from known varieties and inserted in stocks by M. Zen, but nothing particularly different was observed in the mode of budding; nevertheless, when the plants bloomed, the flowers were found to vary from the kinds budded in a most extraordinary manner. Here the case rests, and before we condemn M. Zen's assertions we must remember the curious sportive character of cultivated Roses, nearly, if not all, our Moss Roses, both red and white, having originated as sports from the Cabbage or Provence Rose, and have been since perpetuated by grafting. Grafting often proves a great disturbing cause in vegetable life, and increases the sportive tendency of many of our popular ornamental shrubs and trees to an almost surprising extent.
[CybeRose note: Du Breuil (1873) reported on an experimenter at Bagnéres-de-Bigorre who produced roses with variegated flowers by taking under-developed buds from the bases of canes for budding. Also see Burbidge, 1877]
Of late years many experiments have been made in grafting the Grape Vine, and some useful knowledge as to the influence of stock on scion and scion on stock has thus been gained. There is one thing, however, which is apt to be forgotten in records of grafting, but which I am fully convinced affects the results obtained much more than is generally supposed. For example, a stock which is allowed to bear foliage and fruit of its own, and the same stock headed off and only allowed to bear the leaves and fruit of the scion, give very different results, as the stock which is allowed to retain its own leaves naturally retains more of its own constituent juices and constitutional characteristics than in the other case.
It appears to me that the whole question of the reciprocal influence of scion and stock hangs on constitutional vigour, that is to say, a strong-growing scion will overrule and add vigour to a feeble stock; while, on the other hand, it is well known that a moderately vigorous stock strengthens and invigorates a feeble scion. The effects of constitutional vigour, to whatever cause, it may be due, is seen when three or four varieties—Plums, Roses, Apples, or Pears—are worked on the same stock. Instances are on record where stocks influence the habit of the same plant in a most remarkable manner. Thus, in the "Revue Horticole" for 1867, M. Briot states that Libocedrus tetragona succeeds as a scion on Saxegothaea, and its habit, in consequence, becomes changed into a wide-spreading head instead of forming a narrow cylindrical column; while, on the other band, Chamaecyparis obtusa pygmaea grafted on Biota or Thuja, or if propagated from cuttings, the plants spread horizontally along the ground.
A most complicated and instructive experiment in grafting is recorded in the "Revue Horticole" (1867), from which it appears that M. Carillet, of Vincennes, took two young Pear trees, each of which was worked on the Quince stock, and one of these (Beurré d'Aremberg) was made to serve as the stock, while the other (Beurré de Charneu) was grafted upon it in an inverted position, having its roots fully exposed to the air. The operation was performed in April, 1866, and, during the summer, the stock grew vigorously, flowered, and bore two fruits, while the scion tree threw out buds and shoots from the Quince stock. We are not told whether the scion tree was headed back after the union was effected, but doubtless such was the case. To add to the complexity of this experiment, M. Carillet grafted four Pear scions on the principal roots of the Quince; and two of these succeeded. No intermixture of individual characteristics took place here, although the sap passed from Quince roots through Beurré d'Aremberg, thirdly through the inverted Beurré de Charneu, then through the Quince again, and finally into the two varieties of Pears.
We cannot have too many records of experiments in grafting or budding, and their attendant results, provided that they are recorded fully and intelligently; and, without this, they are valueless for all practical purposes. In several cases, it has been proved that annual plants may be rendered perennial by using them as stocks for perennial species; but this is scarcely to be attributed to the influence of the perennial scion, but is rather owing to the annual having been prevented from flowering and perfecting its seed. Annuals soon commence to die off after their seeds ripen, just as the petals of flowers fade after the ovules are fertilised. It is a little singular to note that instances of endogynous grafting are almost unknown, and deciduous scions on an evergreen stock are rarely successful. The above are only a few of the numerous instances of grafting, which are both curious and interesting, and, at the same time, links in a chain of evidence most important to cultivators. Those who wish to pursue this subject still further, should read a valuable paper on it in the "Popular Science Review," 1871. — F. W. B.