Key to overwintering tropical plants is to prevent from freezing

QA couple of years ago I bought a Bougainvillea in bloom. It was very nice and at the end of season I brought it into my garage. The first thing it did was lose all leaves and I thought it was dying. However, I would scratch the surface of branches and always found living green. I almost gave up but pruned it to about 6 inches high and took it back outside in the sunshine when weather permitted. The result was great — it grew to about 6 feet in diameter and had many blooms.

AIf you don’t have space indoors or have access to a greenhouse, the key to overwintering tropical blooming plants is to prevent them from freezing. They usually defoliate or die back in the process of surviving with little to no light and low temperatures in a garage, but they can survive. Pruning them back to live wood and moving them out is by far the best thing you can do in the spring. Even plants that don’t die back need to be pruned since bougainvillea blooms on the new growth. If you leave older woody stems, they won’t grow much and then you will see fewer blooms. Re-potting can help with some tropical plants. Do keep in mind that bougainvillea does tend to bloom best if it is slightly pot-bound, but if it is too root-bound then it makes it difficult to keep watered during the summer.

QI planted zinnias at my home garden in west Little Rock and they did fine. I also planted them at my garden space at Pulaski County Garden Center at Two Rivers Park. These, however, developed large black spots on the leaves and the flowers did not fare well. Any solution for next year?

AMy guess is that your zinnias at the park suffered from alternaria blight which causes brown blotches on the leaves. Unfortunately the fungus can persist in the soil as well as the seeds, so don’t use any saved seeds from that location in your home garden. I would also recommend planting some other annual for the next couple of years at the park.

Retired after 38 years with the University of Arkansas Cooperative Extension Service, Janet Carson ranks among Arkansas’ best known horticulture experts. Write to her at P.O. Box 2221, Little Rock, AR 72201 or email jcarson@arkansasonline.com.