Despite its name, a potato bush (Solanum rantonnetii or Lycianthes rantonnetii), grown in U.S. Department of Agriculture plant hardiness zones 9 through 11, does not produce potatoes. To confuse things even further, you can even train a potato bush into a tree. If you don't want to grow this shrub into a tree, regular pruning is still a must to encourage new growth on which this plant blooms, maintain a neat and tidy appearance, and keep it healthy.
Spray pruning shear blades with a disinfectant household spray, or soak them in 1 part bleach and 3 parts water solution for five minutes before use. Rinse with water and air dry. This gardening habit helps prevent disease from spreading in the garden.
Make clean, sharp cuts through dead, damaged, pest-infested and diseased stems to remove them from the plant. Perform this type of pruning any time of the year.
Prune the lower branches right above the main stem if you want to form a trunk and train the plant to grow as a tree. Cut the rest of the stems -- up to one-third their overall length -- to shape the canopy of the "tree" or to form a bush-like plant. Perform this type of pruning in late winter or early spring before flowering.
Shear off the flowers after blooming to shape a potato bush back into a formal-looking shrub or tree, if desired.