To keep a mandevilla plant healthy through the winter, people should care for the plant indoors unless living in a year-round warm climate. The plant can only tolerate a minimum of 55 degrees Fahrenheit. Water Mandevailla plants watered sparingly so the soil does not dry out completely.
Prune back a mandevilla plant in late fall before moving indoors during the winter. The flowers at the tips of new branches bloom more when pruned regularly. Place the plant near a window for sun exposure when stored indoor. A mandevilla plant can thrive in a large container or pot with drainage holes.