Propagation is effected by seeds and offsets.
Hyssop (Hyssopus officinalis). Labiatæ.
Seeds. Division.
Iberis (Candytuft). Cruciferæ.
The annuals and biennials are increased by seeds sown in light sandy soil, in spring or autumn. The sub-shrubby sorts are also increased by seeds sown in spring, but more often by divisions or by cuttings.
Idesia. Bixineæ.
Seeds may be sown in spring in gentle heat. Half-ripened cuttings may be made in spring or autumn, and should be inserted in sandy loam, and placed under a bell-glass, in gentle heat. Also by root-cuttings.
Ilex, including Prinos (Holly). Ilicineæ.
Seeds, which should be stratified. They are often cleaned of the pulpy coat by maceration. The seeds rarely germinate until the second year. Varieties are perpetuated by graftage. The veneer-graft, upon potted plants, is usually employed, but other methods may be successful. Budding is sometimes performed.
Illicium (Aniseed-tree). Magnoliaceæ.