Q: I have a royal robe potato bush that when planted last year grew beautifully! I live in Hayden so the plant is in the full sun all day.
This year, however, it is not doing well at all. I believe the reason is that it was hit hard during the winter freeze. I trimmed the branches back to about 10 inches from the roots. Even though the branches are very dry and snap off easily there are actually some green leaves growing on a few of the branches. Should I just dig it up and start over, or wait awhile to see if it comes back to the original beauty I had from the beginning?
A:Β The royal robe potato bush (Lycianthes rantonnetii or Solanum rantonnetii) is a tropical plant that originated in South America. It grows well in our heat with adequate water but needs a little protection in the winter if temperatures get below freezing. Because potato bushes flower on new wood, prune them in winter before they start to put out new growth. You can prune them as early as they have finished blooming for the year. The golden rule of pruning is never take off more than a third at one time to avoid stressing out the plant. Since yours has new growth showing, you could see how it grows before giving up and starting over.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed toΒ tucsongardensage@gmail.com
