The experiments were undertaken primarily for the purpose of learning the best methods of grafting herbs, but a secondary and more important object was the study of the reciprocal influences of stock and cion, particularly in relation to variegation and coloration. This second feature of the work is still under way, in one form or another, and we hope for definite results in a few years. As a matter of immediate advantage, however, herbaceous grafting has its uses, particularly in securing different kinds of foliage and flowers upon the same plant. There is no difficulty in growing a half dozen kinds or colors, on geraniums, chrysanthemums, or other plants from one stock of the respective species.
Six hundred grafts were made in our trials last winter. It was found that the wood must be somewhat hardened to secure best results. The very soft and flabby shoots are likely to be injured in the operation of grafting, and union does not take place readily. Vigorous coleus stocks, three months old, gave best results if cut to within two or three inches of the pot and all or nearly all the leaves removed from the stump. Geraniums, being harder in wood, made good unions at almost any place except on the soft growing points. The stock must not have ceased growth, however. Most of the leaves should be kept down on the stock. Cions an inch or two long were usually taken from firm growing tips, in essentially the same manner as in the making of cuttings. Sometimes an eye of the old wood was used, and in most cases union took place and a new shoot arose from the bud. The leaves were usually partly removed from the cion.
Various styles of grafting were employed, of which the common cleft and the veneer or side graft were perhaps the most satisfactory. In most instances it was only necessary to bind the parts together snugly with bass or raffia. In some soft wooded plants, like coleus, a covering of common grafting wax over the bandage was an advantage, probably because it prevented the drying out of the parts. In some cases, however, wax injured the tissues where it overreached the bandage. Sphagnum moss was used in many cases tied in a small mass about the union, but unless the parts were well bandaged the cion sent roots into the moss and did not unite, and in no case did moss appear to possess decided advantages. Best results were obtained by placing the plants at once in a propagating frame, where a damp and confined atmosphere could be obtained. In some plants, successful unions were made in the open greenhouse, but they were placed in shade and kept sprinkled for a day after the grafts were made. The operation should always be performed quickly to prevent flagging of the cions. Or, if the cions cannot be used at once, they may be thrust into sand or moss in the same manner as cuttings, and kept for several days. In one series, tomato and potato cuttings, which had flagged in the cutting bed, revived when grafted. And cuttings which had been transported in the mail for three days grew readily, but they were in good condition when received. The mealy bugs were particularly troublesome upon these grafted plants, for they delighted to crawl under the bandages and suck the juices from the wounded surfaces.