Nandina domestica is an evergreen to semi-evergreen shrub in the barberry family, native to eastern Asia from the Himalayas to Japan and unrelated to true bamboos. It is the sole species in its genus. Gardeners value it for consistent year-round interest: new foliage emerges bronze-red, shifts to green through summer, then turns burgundy to scarlet in fall and winter. Loose panicles of small white flowers appear in early summer, followed by dense clusters of red berries that persist into winter.
Plants tolerate a wide range of soils and become drought tolerant once established. In zone 6 they may defoliate in hard winters but typically regrow from the base. Nandina spreads by underground runners and by seed dispersed through bird consumption of the fruit. It has naturalized and is considered invasive in parts of the southeastern United States; check local regulations before planting. Removing the oldest canes at ground level every two to three years prevents legginess and promotes dense, multi-stemmed growth.
The fruit, known as nanten in Japan, has a documented history in Kampo and traditional Chinese medicine as an antitussive. Roots contain berberine, an alkaloid with documented antibacterial and anti-inflammatory activity also found in goldenseal and Oregon grape. All parts carry cyanogenic glycosides; berry ingestion in quantity has caused fatality in cedar waxwings, and the plant is toxic to mammals including pets.
Fungal leaf spot
Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.
Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.
Root rot
Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.
Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.