Winter Mandevilla Care
Mandevillas are one of my favorite tropical plants. I purchased two plants late last summer that I was able to keep through the winter. This year they rebounded and have been real showstoppers!
I have them planted in large square terra cotta containers that are fitted with 5 foot tall tuteurs. The tuteurs were actually a mistake. I sent the carpenter the wrong measurements and they turned out to be way too tall for the plant I originally had in mind, but they ended up working quite well with the robust mandevillas.
Mandevillas are cold hardy to zone 9, which means they need to be moved indoors when temperatures consistently drop down into the lower fifties, although they can survive a few nights in the upper forties. The best time to make the move is when you bring your houseplants inside, which is usually done when indoor temperatures are similar to those outdoors.
If you have plenty of sunlight and room you can treat your mandevilla like a houseplant and keep it inside your home over winter. I've never tried this but I have been told that it works. Place the plant in a sunny location and water it about once a week. It may go dormant anyway and lose its leaves, in which case you should cut back on watering severely to prevent root rot.
I keep my mandevillas in my lathe house. This is an open potting shed that I cover in heavy plastic during the winter to create a semi-greenhouse effect. You can keep a mandevilla any place where temperatures stay between 55 and 60 degrees, such as a basement, crawlspace or garage.
If your mandevilla is planted in the ground it will need to be dug up and transplanted to a container. Select a pot large enough to accommodate the root ball.
Cut the plant back to about 12 inches above the soil and then wash the remaining leaves to remove any pests you don't want to over winter with the plant. If your mandevilla is growing in a container you may want to flush the soil with water to eliminate ants, spiders and the like.
Once the plant is moved into storage cut back on water. You really only need to water it occasionally. Just don't let it dry out completely. And there is no need to fertilize the plant over winter at all.
In the spring after all danger of frost has passed and temperatures are consistently above 60 degrees F, you can move your mandevilla back outside. Don't be alarmed if growth produced over winter burns off. This is fairly routine.
Begin watering on a regular basis and feed with a liquid fertilizer and in no time you will have beautiful flowers again!