Passiflora caerulea

Passiflora caerulea, the blue passionflower, bluecrown passionflower or common passion flower, is a species of flowering plant native to South America that has been introduced elsewhere.
It forms a vigorous, deciduous or semi-evergreen tendril-bearing vine growing to or more. Its leaves are palmately lobed, and its fragrant flowers are blue-white with a prominent fringe of coronal filaments in bands of blue, white, yellow, and brown. The ovoid orange fruit grows to across.
The fruit is edible, but is sometimes described as having an unpalatable or unpleasant flavour. In South America, the plant is known for its medicinal properties, and is used by both the Toba and the Maka peoples.

Description

Passiflora caerulea is a woody vine capable of growing to high where supporting trees are available. The leaves are alternate, palmately five-lobed, and are up to in length while being linear-oblong shaped. The base of each leaf has a flagellate-twining tendril long, which twines around supporting vegetation to hold the plant up.
The flower is complex, about in diameter, with the five sepals and petals similar in appearance, whitish in colour, surmounted by a corona of blue or violet filaments, then five greenish-yellow stamens and three purple stigmas. The fruit is an oval orange-yellow berry, long by in diameter, containing numerous seeds.

Chemical constituents

Compared to P. incarnata, this plant contains higher amounts of the MAO-inhibitor harmine.

Etymology

The specific epithet caerulea means "blue" and refers to the blue coronal filaments.

Cultivation

Passiflora caerulea is widely cultivated as a wall-climber or as groundcover. It is a hardy species, able to survive winter temperatures as low as, although it requires a sheltered position facing south or west. It can become invasive, the twining shoots constantly appearing unless eradicated. It is the only Passiflora species that volunteers in California. It has gained the Royal Horticultural Society's Award of Garden Merit.

Cultivars

A number of cultivars have been produced from the species:

'Chinensis'
'Constance Elliott' was raised by Lucombe, Pince & Co in Exeter, Great Britain in 1884. It has pure white, fragrant flowers; not as free-flowering as many other clones. It has also won the Award of Garden Merit from the Royal Horticultural Society.
'Pierre Pomie', a pale pink flower form
Uses

The fruit is edible to humans when ripe, but its flavour has been described as bland, undesirable or insipid. If allowed to fully ripen in a warm climate and fall naturally from the vine, it has a mild blackberry flavour, though with a lower sugar content than commonly eaten species.
A tea can be made of the flower or leaves; but the leaves contain tetraphyllin B and epi-tetraphyllin B, cyanogenic glycosides that liberate hydrogen cyanide when activated by enzymes. It is possible to boil away most of the cyanide.
In South America, the plant is known for its medicinal uses. It is used in both herbal tea and dietary supplements, as well as in marmalades, ice creams, syrups and beverages. It is also used by the indigenous Argentinian Toba and Maka people.
Passiflora caerulea is sometimes used as a rootstock, to which is grafted a scion of the edible P. edulis.

In culture

Passiflora caerulea is the national flower of Paraguay. Its intricate structure has generated Christian symbolism, each part representing a different part of the Passion of Christ.