Passion flowers are aptly named. They were once associated with the Passion of Christ because of the shape of their corollas, each part of which is supposed to evoke the crucifixion scene.

Today, these marvels of nature, also known as passiflora, are all the rage of gardeners and lovers of plant curiosities – not to mention chefs who enjoy the sweet-tasting fruit of certain species! You only have to look at their flowers to be seduced.

Each corolla has ten petals and sepals, adorned with a crown of long filaments, stiff or twisted, depending on the variety, and often bi-coloured. It's topped by imposing stamens and, above all, an astonishing pistil with three stigmas, often in contrasting shades.

In terms of colour, passion flowers come in pure or pinkish white, cream, mauve and all shades of purple. The most exotic species are coloured bright red, fuchsia, purple, golden yellow or pale green-yellow... what a poem! Most passion flowers are native to the tropical countries of Latin America. Many species are cold-blooded and cannot be grown outdoors in our temperate climates.

Passiflora: the hardiest species

Some, however, can be planted in the ground, as long as the region has a mild winter. Sheltered gardens can also accommodate certain passifloras. Hardy passion flowers come from American countries where the climate is similar to our own. Thanks to cross-breeding in horticulture to increase plant vigour and hardiness, there are now more and more frost-resistant varieties.

• Passion flower incarnata (Passiflora incarnata) is a naturally hardy species, able to withstand temperatures as low as -25°C! Its corollas are white with white and purplish striped filaments.
• Blue passion flower (Passiflora caerulea) is the most widely cultivated species in Europe. Its petals are white, but its crown of filaments is dark violet-blue with white stripes, and its pistil is violet-black. It flowers generously in summer and produces tasty fruit if it gets enough sun. This hardy species can withstand temperatures as low as -15°C, although its foliage disappears at -8°C.
• Colvills passion flower (Passiflora x colvilii) is an old hybrid that has proved its worth. Hardy to -12°C, it has pretty flowers with white petals and long, almost entirely violet filaments.

All these species thrive in summer and will climb any surface. Some, if they really like it, spread out widely, weaving a curtain of vegetation several metres high and several metres wide! Passifloras have the advantage of camouflaging old fences or decrepit walls, so don't hesitate to place them in unattractive places, as long as the location is well exposed to the sun.

Passiflora: sumptuous but cold varieties

For lovers of exotic plants, non-hardy passifloras are real jewels, best grown in a greenhouse or at home. A heated conservatory with high humidity is ideal, as these tropical beauties come from tropical forests where the atmosphere is warm and humid.

Many species are brilliantly coloured, such as Passiflorale coccinea, with its large scarlet flowers, red and white filaments, green and red pistil and stamens. As for the winged passionflower (Passiflora alata), it has large flowers with pinkish-red petals topped with curly filaments striped with white and purple. Hardy or not, passion flowers have charm to spare and, over the years, they'll always win you over... as long as they're well cared for!

Passiflora: the golden rules!

• Hardy passionflowers should be planted against a south-facing wall.
• The soil should be well-drained and not retain moisture in winter, which can cause root rot.
• The soil must not be too chalky, otherwise the foliage will fade and the plant will become brittle.
• Water the base and foliage regularly in summer, as passionflowers do not tolerate drought.