Passiflora quadrangularis seeds - Giant granadilla

Passiflora quadrangularis, the quadrangular-stemmed passionflower, owes its name to the unique shape of its stems, which have four faces with sharp, membranous angles. This tropical climber reaches enormous dimensions in its natural habitat. In our climate, it will be less imposing but make a beautiful greenhouse or conservatory plant. We love its large, fragrant, crimson red flowers, topped with a crown of curly filaments blending violet and white. After flowering, edible fruits appear, green-yellow when ripe, called grenadillas, prized for their fragrant flesh.

Passionflowers belong to the vast Passifloraceae family, which includes nearly 400 species and numerous natural or horticultural hybrids. Mostly native to the tropical regions of South America, they come in a multitude of shapes and colours. Passiflora quadrangularis grows in the floodplains of humid tropical forests in Central and South America. In its natural environment, it can exceed 40 m in length, thriving in a warm, humid climate conducive to its expansion. This twining climber clings firmly to its support with long tendrils, allowing it to climb up to 6 m in a pot. It stands out from other passionflowers due to its quadrangular stems with small prominent wings. Its entire and heart-shaped leaves, measure 7 to 13 cm long and 5 to 15 cm wide. They are light green with dark green veins, borne on long, grooved petioles with six nectar-rich glands. The flowering, which spans summer to early autumn, consists of large solitary flowers about 10 cm in diameter, continuously renewing. These delicately scented flowers feature five broad, rosy-red tepals tinged with green inside and greenish on the reverse. Their central crown, formed of filaments streaked with white, pale violet, and deep purple, gives the flower a unique look. Its creamy-white stamen heart changes over time: the petals and sepals curl back, while the crown of filaments folds and then straightens, a natural mechanism preventing self-pollination. Once fertilised, the flowers give rise to large, ovate, 20 to 25 cm long fruits, ripening to an orange hue. Their thick skin protects a sweet, aromatic pulp, filled with numerous flattened seeds.
An interesting feature: the size of the container strongly influences its behaviour. In a small pot, the plant limits its root growth, promoting abundant flowering. Conversely, in a large pot, it prioritises root development at the expense of flowers.

Fresh passionflower seeds germinate easily. However, those that have entered dormancy require specific treatment to sprout.

Not frost-hardy, this Giant Grenadilla will thrive only in a warm greenhouse or bright conservatory, where it will find ideal conditions to grow. It requires rich, moist, well-drained soil and a sunny, sheltered position away from cold draughts. Pruning after flowering helps control its growth and maintain a balanced habit.