Ask The Plant Expert: I have a flower and the name of it is Crimson Mandevilla. I was wondering how to care for it during the winter. The spelling of it may not be exactly right. Can you help? Rhonda Plant Expert Reply: Rhonda, To over-winter Mandevillas, it depends on where you live. Mandevilla (formerly the genus Dipladenia) splendens is hardy in zone 9-11. So if you live in parts of Arizona, California, Texas, Louisiana or in Florida, you can simply leave them outside and water as needed. Preparing Mandevillas For Overwintering However in other places, you will need to pot the Mandevilla and bring it indoors. If your plant is not already in a container, be sure to prune the plant back by a 1/3 to compensate for any roots lost during the transplanting process. Be sure to clean the plant and check for insects before you bring the plant indoors. Remove all dead foliage and check the back of the leaves for insect eggs and larvae. I recommend wiping all the [...]