This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Many hardy trees and shrubs may be raised from leafless cuttings of the well-ripened young shoots. The best time to take these cuttings is about the end of October and during November, although many will also root freely if taken in spring just when the sap is beginning to rise. With hard-wooded cuttings the basal half, being the ripest or most mature, makes the best cutting, and if taken with a "heel" of the older wood attached it is almost certain to root. The cuttings vary from 1 in. or more to 1 ft. in length, and the larger ones may be inserted about three-fourths of their length in the soil when placed out-of-doors. In this way such plants as Gooseberries, Currants, Roses and Rose stocks like the Brier and the Manetti, Dogwoods, Brooms, Cotoneasters, Diervillas (Weigela), Forsythia, Jasmines, Kerria Mock Orange (Philadelphus), Flowering Currant (Ribes sanguineum), Willows, Shrubby Spiraeas, Tamarisk, Skimmias (fig. 63), and many others, are readily raised.
Fig. 63. - Shoot of Skimmia japonica Rooting.
While small herbaceous and leafy cuttings are inserted with a dibber, which is used for making a hole and packing the soil round the base, long woody cuttings are inserted in trenches made with the spade, or they may be inserted with a dibber. In the first case a line is stretched the length of the row, and a trench with a vertical side is made with the spade. The cuttings are then placed against the vertical side of the trench and pushed into the soil, the distance between the cuttings being about 3 or 4 in. The soil is placed against them and trodden down firmly with the feet, being afterwards levelled. When several rows of hard-wooded cuttings are to be inserted, about 1 ft. is left between the rows, to allow room for weeding and hoeing during the season of growth.
Vines may be raised from cuttings inserted in the open air in the way indicated. As a rule, however, they are raised from single eyes inserted in small pots in heat. Clematises may also be raised from cuttings in the same way. With some evergreens, like Aucubas, quite large pieces of a plant having several leafy branches will root readily if placed in coconut fibre or leaf mould with a little bottom heat.