Sweet box is the plant that solves January. The flowers are small enough to overlook entirely, tucked under the leaves in tight cream clusters, and the scent they throw on a mild winter afternoon is honey and vanilla carried twenty feet down a walk. Most people smell a sarcococca before they find one, and then plant three.

These are slow, low, glossy evergreens in the boxwood family, built for the deep shade under trees and along north walls where almost nothing flowers. Sarcococca confusa follows the bloom with glossy black fruit, Sarcococca ruscifolia with red, and Sarcococca orientalis is among the freest flowering of the group. Deer leave them alone, drought bothers them less than the delicate look suggests, and the plants stay tidy without pruning. Site a sarcococca beside a door or along a path you use in winter, which is the only way to collect on the investment.