Skimmia.—Requires no pruning.
Smilax.—The hardy species of this genus do not require any pruning if they have room to ramble. If space is restricted, thin out and shorten in autumn.
Sophora.—These should be kept thinned when they have attained flowering size; in a young state they should be kept to a single stem and induced to form well-shaped trees.
Spartium.—This should be cut back in a small state, but when older it requires no pruning whatever.
Spiræa.—Though all the Spiræas will flower on the old wood, the following are better for being cut back in winter to form young flowering shoots, viz., S. betulifolia, S. Douglasi, S. Foxii, S. japonica, S. Margaritæ, S. salicifolia, S. semperflorens, S. tomentosa, and many of their varieties and hybrids. The remaining Spiræas should be kept thinned out, and if any are making strong young breaks from the lower part of the plant they can be cut back to them after flowering.
Stachyurus.—This should be thinned out after flowering.
Staphylea.—S. pinnata should be kept thinned in late summer; S. colchica and S. Coulombieri require very little pruning, but if too tall or unshapely should be cut back immediately after flowering.
| Stuartia | } | Require no pruning. |
| Styrax |
Suæda.—Cut back occasionally to keep it from getting ragged.
Symphoricarpus.—Keep these well thinned out, which should be done in late summer.