Passion flowers (Passiflora spp.) are tropical or subtropical vines, meaning they thrive in warm climates. In cold climates, temperatures below freezing (32°F/0°C) can damage or kill the plant. The roots, stems, and leaves are particularly vulnerable to frost. Some species, like Passiflora incarnata, are hardier and can survive light frosts, but most require protection to overwinter successfully.
Before the first frost, prepare your passion flower for dormancy. Reduce watering gradually to slow growth and allow the plant to harden off. Prune back dead or weak stems to minimize disease risk, but avoid heavy pruning—this can stimulate new growth that won’t survive the cold. Remove fallen leaves and debris around the base to prevent fungal infections.
3.1 Container-Grown Passion Flowers: These are easiest to protect. Move the pot indoors to a cool (45–55°F/7–13°C), bright location like a garage or sunroom. Water sparingly—just enough to keep the soil slightly moist. The plant may lose leaves, but it will regrow in spring.
3.2 In-Ground Plants: For hardy species, mulch heavily (6–12 inches) around the base with straw or leaves to insulate roots. For tender varieties, dig up the plant, trim roots and stems, and pot it to bring indoors. Alternatively, cover the plant with burlap or frost cloth on cold nights.
If brought indoors, place the passion flower near a south-facing window for adequate light. Reduce watering but avoid letting the soil dry completely. Humidity is often low indoors, so mist the plant occasionally or use a humidifier. Watch for pests like spider mites, which thrive in dry conditions.
During winter, the plant may enter dormancy, appearing lifeless. This is normal—avoid overwatering or fertilizing. As temperatures rise in spring, gradually reintroduce the plant to outdoor conditions. Start by placing it in a shaded area for a few hours daily, increasing exposure over 1–2 weeks. Resume regular watering and fertilizing once new growth appears.
In very cold climates, even hardy passion flowers may die back to the ground. Protect the roots by layering mulch and covering the base with a breathable fabric. If the roots survive, the plant may regrow from the base in spring. In borderline zones, planting near a south-facing wall can provide extra warmth.
