Passionflower: how to protect it from the cold?

Some varieties are more or less hardy.

The passionflower is a plant that is usually not very hardy and tolerates only light frosts. The hardiness of a passionflower largely depends on its variety: not all are equal when it comes to the cold. Some passionflowers are frost-sensitive, such as the Passiflora edulis, which bears the passion fruit, or the Passiflora quadrangularis, with spectacular flowers, which do not tolerate temperatures below 0°C. For these frost-prone plants, wintering indoors or in a heated greenhouse is essential for their survival. In cold regions, opt for container cultivation, which makes it easy to move the plant indoors during periods of severe cold. They make very beautiful plants for warm greenhouses or conservatories. The hardier ones, such as the Passiflora caerulea, and Passiflora incarnata, the common passionflower, withstand temperatures of -10°C to -12°C, in well-drained soil and placed in a position sheltered from cold and desiccating winds. They are hardy enough to stay in the ground all winter in regions with mild winters (in the olive-growing zone and along our country’s Atlantic coast).

The Passiflora edulis, which bears the passion fruit, and Passiflora quadrangularis: two frost-sensitive species that require protection from winter cold!

When should you overwinter a passionflower?

That will depend on its cold tolerance! As long as the weather stays mild and dry, it won’t be harmed. But as soon as the weather turns cold and damp, even if there is no frost yet, the potted passionflower should be sheltered. Generally, start preparing your passionflower for winter before the first frosts and especially if a cold spell is forecast. It will usually be around the end of autumn or the start of winter, that is, around mid-October in northern France, and around mid-November in southern France.

How do you overwinter a passionflower in a pot?

• In mild regions where winter temperatures do not fall below around -10°C, you can leave your passionflower in a pot to overwinter outdoors (for the hardiest varieties). Nevertheless, bear in mind that in a pot, roots are more exposed to frost than when grown in soil. Place the pot at the base of a well-exposed wall sheltered from cold winds. Do not hesitate to prune before overwintering by cutting back the main shoots. Mulch the base with a thick layer of straw or fallen leaves. Then wrap the container with insulation such as bubble wrap, cardboard or jute. In case of severe cold, wrap it all in a winter fleece. In spring, you can remove these protections.
• In regions with severe winters, bring the pot indoors to shelter from the cold in a greenhouse, a heated conservatory or in a frost-free, very bright room at around 12–15°C. Mist the leaves from time to time to help it cope with the dry atmosphere caused by heating. Indoors, it can be attacked by red spider mites; these regular mistings will help prevent these mites from appearing. You can bring the pot back out after frosts, from March to May depending on the region.

Potted passionflowers can easily be brought under cover for the winter. Here, Passiflora caerulea

How do you overwinter passionflower in the garden?

It’s best to keep a close eye on it to help it get through winter in the garden:

• Mulch the stump with a thick layer of mulching to protect from the cold.
• If severe frosts are forecast, strengthen the protection by wrapping the branches under several layers of fleece which will retain heat and protect them from wind, rain, or even snow. Secure the fleece with ties so that it stays in place throughout the winter. Occasionally lift it slightly when the weather is sunny and dry. This protection is not needed in southern France.
• Water only sparingly in winter.
• As temperatures begin to rise and the major frost risk has passed, you can remove this protection.