I currently have a beautiful Mandevilla and would like to preserve it for the winter months. Any tips?
There are many varieties of Mandevillas, including varieties formerly known as Dipladenia. The old fashioned variety Mandevilla x amabilis Alice du Pont has fuzzy foliage and bright pink flowers, grows vigorously. Among other cultivars Mandevilla splendens (Dipladenia splendens) has a dark glossy leaf. Both are grown trellised and have a tendency to vine.
These species of tropical vines hardy (depending on cultivars) in zones 9-11 winter over only in the tropical South. They tolerate a minimum temperature of 45-50F at which time growth will begin to slow down. For winter storage keep the plant outside as long as possible before bringing it indoors. Check for insects and use insecticidal soap if needed.
To winterize the plant;
Treat it as a houseplant or store it in a dormant stage.
Mandevilla as a can be trimmed back to make it manageable and needs a sunny window to flourish indoors. Water once a week. You will get some leaf drop due to lower light and humidity indoors.
2. Dormant stage
Another way to winterize mandevilla is in a dormant stage in a garage or cool basement with temperatures around 45-55F. Cut it back to about 12 inches above the soil line. Treat for insects if needed. Keep it dry but not completely dry. Check periodically for soil moisture. Mandevilla will eventually drop all its leaves. The important thing to keep in mind is that you want to keep it alive it through the winter.
In the spring, some of the spindly winter growth may be pruned back and when new shoots develop move the plant to a sunny window. Pinch the new growth to get a bushier plant. Repot in fresh soil and set outside when danger of frost has passed.