Carmichælia.—Requires no pruning.
Cassandra.—See Calluna.
Cassinia.—These are grown more for their foliage than for their flowers, and should be cut down in the winter or early spring. This can be done annually or biennially according to whether the plants are growing strongly or not.
Cassiope.—See Calluna.
Catalpa.—This genus contains some of our handsomest flowering trees, all of which require careful pruning after the flowers are past, thinning out the weakly wood, and shortening any long branches.
Ceanothus.—Of these, C. americanus, C. azureus, C. integerrimus, and the garden hybrids, such as "Gloire de Versailles," "Marie Simon," "Ceres," &c., flower on the young wood, and should be cut back in spring, allowing only sufficient shoots to remain to form a well-balanced plant, and shortening them back to within two or three eyes of the old wood. The remaining species flower on the old wood, and merely require a shortening back of the stronger shoots and a thinning out of the weakly ones after the flowers are past.
Celastrus.—A climbing genus of strong and vigorous habit with showy fruits. They only require sufficient pruning in winter to keep them within bounds.
Cercis.—Requires no pruning, except such as may be necessary to make well-shaped plants, which should be done after flowering.
Chimonanthus.—The shoots of this should be shortened back after flowering, and if on a wall they should be spurred in.
Chionanthus.—See Cercis.