Aucuba japonica var. borealis

Aucuba japonica is one of the great problem-solvers of the shade garden, a glossy broadleaf evergreen that thrives in the dry, difficult shade where few other shrubs will, and var. borealis is the toughest of the clan. Drawn from the cold northern reaches of the plant's Japanese range, this small-leaved form was selected for hardiness, holding very shiny, dark green, leathery leaves through winters that would burn a common aucuba. The genus name is a Latin rendering of the Japanese aokiba, for the ever-green leaves.

Where most aucubas are content only from the middle South and warmer, var. borealis pushes the boundary north, recorded surviving four degrees Fahrenheit at the U.S. National Arboretum in the winter of 1994. That cold tolerance, roughly to USDA zone 6, makes the northern Japanese aucuba a rare thing, a broadleaf evergreen for shade in gardens too cold for the rest of the genus. Like all aucubas, the plant is dioecious, and female plants carry glossy red berries into winter when a male grows nearby.

Aucuba has long been a city gardener's ally, shrugging off pollution, salt, deep shade, and neglect, and this hardy form brings that resilience to colder ground. Set the shrub in part to full shade in good, moisture-retentive but well-drained soil, as a foundation planting on a north wall, a filler in a shaded border, or an evergreen anchor in a woodland corner. The small, dark, lacquered leaves catch what little light reaches them and give substance to the dim places.

The small maroon spring flowers pass almost unnoticed, for the ornament here is the foliage and, on pollinated females, the scarlet fruit. A gentle caution worth noting: the leaves and berries contain compounds that can cause stomach upset if eaten, so site the plant accordingly where small children graze. Slow, durable, and quietly handsome, var. borealis rewards the patient gardener with decades of evergreen presence.