How to Prune Nandina Domestica

Nandina domestica is an ornamental shrub commonly known as nandina or heavenly bamboo because of its bamboo-like leaves and upright canes. Although native to Japan, India and China, it is grown widely throughout the southern United States for its colorful foliage and glossy red berries. However, if left unattended for several years, the shrub can become leggy and the lower canes become bare. Careful yearly pruning can result in a full, healthy-looking plant.

Nandina is a broadleaf shrub that thrives in U.S. Department of Agriculture plant hardiness zones 6 through 9. It is evergreen in zones 8 and 9, but deciduous if temperatures fall below 10 degrees Fahrenheit, typically in zones 6 and 7. This multi-caned shrub provides year-round interest in the garden with small clusters of whitish flowers and yellow anthers in the spring, followed by red berries that persist through winter. The leaves transition from a spring green through an attractive range of reds and green into the winter. Nandina grows well in light shade to full sun. Although nandina prefers moist loamy soils, it can tolerate drought conditions.

Pruning once a year is sufficient to restore or maintain a nandina. The optimal time for pruning is in late winter before new plant growth occurs in early spring. Pruning later in the season will remove growth tips and result in lost flowers and berries, which are focal points of interest later in the season. However, dead canes and branches can be removed at any time. Several branches can also be cut for decorative display in floral arrangements or wreaths at any time without damaging the plant.

Pruning can be done with clean hand pruners or loppers. Before and after use, clean pruning tools with a solution of 1 part bleach and 3 parts water for five minutes before air-drying to prevent spread of disease. Begin by evaluating the plant. Are there dead areas or areas that are too thick? The goal is to thin and balance the shrub. Follow the pruning "rule of three" that recommends cutting one-third of the canes at ground level, cutting one-third of the canes at intermediate heights and leaving one-third of the canes untouched. Select the oldest canes for cutting to the ground and attempt to space those throughout the shrub. If possible, leave the younger canes uncut. This should result in a well-shaped healthy-looking plant.

Several points should be considered when planting or working with nandina. First, nandina is now considered an invasive species in a number of Southern states including Texas. It spreads by root sprouts or seeds and displaces native plants. Check state invasive plant databases for the status of nandina in your area. Second, although no toxicity has been reported in humans, ingested berries can be toxic to cats and some grazing animals; nandina should be kept away from pets and not be allowed to naturalize into grazing areas.