Pruning Time for Nandina

Time Frame

• The proper time to conduct pruning on any heavenly bamboo shrub is when it's dormant, especially from midwinter to mid-spring. If flowering and berry production is not desired, pruning can occur up until late spring or very early summer. Flowers and fruits occur on tissues that originate on wood that sprouts in spring, also called new or current-season wood. Dead, diseased or broken stems and leaves on a heavenly bamboo may be removed any time of year.

What to Prune

• The growth habit of heavenly bamboo is an upright clump, so any pruning done on the few stems is quite evident and can look unsightly if overdone. Gardeners usually do not cut back all stems of a heavenly bamboo to the ground in late winter. Although the plant rejuvenates, this harsh treatment can weaken plants if growing conditions aren't ideal or the plant is old or stressed by drought, disease or insect problems. Trim back errant stems to retain the pleasant silhouette of the plant.

Annual Maintenance

• To keep the heavenly bamboo plant looking its best and having a continual renewal of foliage, prune stems at different levels each late winter. Count the number of stems in the clump. Cut one-quarter of the stems back to stubs flush to the ground, and cut another quarter of the stems back by one-third of their height and another quarter back by two-thirds their height. Leave the last quarter of stems their original height. The result is new growth of tufted leaves at multiple heights, creating a uniform, lush plant clump.

Insight

• On heavenly bamboo plants that bear the drooping clusters of red berries, trim some branch tips to harvest the fruits to use for Christmas decorations. You may further cut back the branches in late winter as needed to maintain the usual one-quarter trimming schedule. Although you can trim back plants anytime in winter, wait until late winter after the coldest weather passes, so you can see which branches sustained the most damage from cold and remove them during the pruning event.