Overwintering Mandevilla in Pennsylvania: Prune, Cool, Dry

Bring your Mandevilla in before frost. As nights cool to 40s°F:

1. Feed with high-phosphorus fertilizer (10-56-14) at half rate to harden growth.
2. After 3 weeks, prune hard to 12″ above soil.
3. Treat for pests (spray alcohol-soap).
4. Store in unheated garage/cellar (above freezing) or bright cool room.
5. Water very sparingly—keep dry side.
6. In spring, move out; expect winter growth to burn off.

This method has worked for many growers.