The division of the rootstock is a method of propagation applicable to the majority of perennial plants. In the case of most corms and bulbs, it is necessary, in order to increase the supply, to separate the young bulbels or cormels and to plant them out in a nursery bed until they develop to a useful flowering size. But in the division of the rootstocks of herbaceous plants a certain amount of violence is usually required, and a strong knife, a cold chisel and a mallet will be found useful tools. Each plant, if it is to develop into a new plant, must include at least one eye or bud and must usually also be provided with a supply of rootlets.

Many plants may be propagated by the process known as layering, which essentially consists in pegging down a shoot to the ground by means of a little crotchet stick, having notched with a sharp knife half way through a joint at the point where the shoot touches the soil, and covering the pegged down part of the shoot with a few inches of good gritty loam. In a little while, roots will form at the point of section and the shoot can be separated from its parent as an independent plant. The Carnation is usually propagated in this way, the layering being performed in July and the young plants being separated a few months later. Roses may be pegged down and layered in a somewhat similar way, but in their case it is the middle of a branch and not its base which is cut and pegged beneath the soil.

Another method by which many plants can be increased is that of cuttage. This is the method usually employed by growers of chrysanthemums, pansies, and certain other plants. To effect this, a cut should be made in a slanting direction through the stem to be severed, just below a joint. As a rule cuttings of herbaceous plants should be made in the spring. Some cuttings will root readily in light soil in the open air if a shady position be selected, but usually it will be found to be desirable to plant the cuttings in pots of sandy loam and to place in a hot bed, shading from the sun until they are rooted.