Passiflora coactilis - Coactilis Passion Flower
Passiflora coactilis is one of the lesser-known yet most intriguing Andean passion flowers. It belongs to the subgenus Tacsonia, a group of around sixty species associated with the cool mountains of South America, whose flowers differ from the classic image of a passion flower: instead of a flat, radial flower with a colorful corona, they have a long floral tube and hang from slender stalks like bells. Among them, Passiflora coactilis stands out for its exceptionally elongated floral column, which can reach eleven centimeters and extend the stamens and style far beyond the corolla.
In Ecuador and southern Colombia, the plant is known as tauso - a name covering several related species with edible fruits, related to the popular curuba (Passiflora tripartita var. mollissima) and banana passion flower (Passiflora tarminiana). It remains rare in horticultural cultivation, available mainly to collectors, although its origin in high mountains means it tolerates cold better than most tropical passion flowers and may be an interesting choice for greenhouses and conservatories in temperate climates.
Botanical description and plant habit
Passiflora coactilis is a perennial, evergreen climber with stems that climb using tendrils emerging from the leaf axils. Young shoots are densely covered with soft, felt-like hairs, while older stems gradually become woody at the base, forming a permanent framework for the plant. The leaves are simple and trilobed, about 6.5-13.5 cm long and up to 15.5 cm wide, with a toothed margin; their undersides are distinctly hairy, giving the plant a characteristic velvety appearance. Stipules grow from the base of the leaf stalk, as is typical of the entire genus.
The flowers are large, solitary, and pendulous. Their most eye-catching feature is the elongated floral tube (hypanthium), from which the sepals and petals emerge in shades of pink. The corona - showy and colorful in many passion flowers - is reduced here to a narrow ring ranging from brownish to purple. An exceptionally long androgynophore projects from inside the flower, a column bearing five stamens and three stigmas, reaching up to 11 cm in length. This structure is an adaptation for pollination by hummingbirds of the genus Ensifera, whose bill and tongue are among the longest in the bird world.
Growth rate and development
The species is one of the fastest-growing passion flowers. Under favorable conditions - good lighting, consistently moist substrate, and moderate temperatures - its shoots extend by several meters over the course of a season. Mature plants in nature and warm climates typically reach 5-10 m, while horticultural sources mention shoots climbing through trees at forest edges that can reach even 20 m in length. In container cultivation, growth is naturally limited by the volume of the root system and can be controlled further through regular pruning, allowing the plant to be trained on a trellis two to three meters high.
Like most passion flowers from the Tacsonia subgenus, Passiflora coactilis usually needs several growing seasons before it begins to flower - only a well-established, partially woody specimen produces buds. With suitable overwintering, the plant is long-lived and rebuilds its crown each year from shoots that survived the winter, or regrows from the base if the above-ground parts were damaged by cold.
Flowering and propagation
In its natural environment, where there are no distinct seasons, flowering may continue for much of the year. In cultivation in a temperate climate, flowers appear mainly during the warm months, from late spring to autumn, on the current season's growth. An individual flower remains open for several days. In nature, pollination is carried out by hummingbirds, so in a greenhouse or conservatory, fruit set usually requires manually transferring pollen to the stigmas, preferably from another plant, because many passion flowers are partially self-incompatible.
The fruits are roundish or ovoid, yellowish when ripe, about 8-10 cm long, with a tough skin and aromatic flesh consisting of numerous seeds surrounded by juicy arils. The flavor is described as sweet and tart, intensely aromatic, and similar to curuba fruit. Locally, they are eaten raw and processed into juices. Besides generative propagation, the species can also be propagated from semi-hardwood stem cuttings rooted in a warm, moist substrate, which preserves the characteristics of the selected plant.
Origin, habitat and environmental requirements
The species' natural range includes the Andes of southwestern Colombia and Ecuador. The plant grows in cool cloud forests and their margins, in thickets and along roadsides, at elevations of approximately 2200-3600 m above sea level. In this zone, temperatures remain in the low teens Celsius throughout the year, nights can be cool, and the air is almost constantly saturated with moisture from fog and frequent rainfall. The soils are rich in humus, acidic, and well-drained.
These origins determine the plant's most important tolerance characteristics. Passiflora coactilis tolerates cool temperatures and light frosts of a few degrees below freezing, but stronger frost damages the leaves and stems, leaving only the plant's base alive. On the other hand, the species does not like temperatures above 30 °C or dry air - under such conditions it drops its buds and the leaves lose turgor. Its water requirement is high, wind tolerance is moderate, and light requirements are high, although young plants and specimens in hot regions respond well to light shade.
Cultivation in a temperate climate
In cooler regions of Europe, Passiflora coactilis is best grown as a container or greenhouse plant. It needs a large pot with drainage holes, filled with humus-rich, well-drained growing medium - a mixture of compost soil with perlite, bark or coarse sand works well, with a slightly acidic to neutral pH. From late spring, once the frosts have passed, the plant can be placed outdoors in a sunny, sheltered position, gradually acclimating it to full light. In summer, water abundantly, and during hot weather provide light midday shade and mist the leaves.
During the growing season, fertilize every two to three weeks with a balanced compound fertilizer; from midsummer, it is worth reducing nitrogen to avoid stimulating excessive shoot growth at the expense of flowering. In autumn, before the first frosts, move the plant to a bright, cool room with a temperature of around 5-12 °C - an unheated greenhouse, conservatory or bright stairwell. In winter, limit watering to a minimum so that the root ball does not dry out completely. In early spring, prune overly long and damaged shoots, which encourages the plant to produce new flowering growth.
In the warmest regions of Europe - on Mediterranean and Atlantic coasts, where winters are mild - growing it in the ground against a south-facing wall may be attempted, with a thick mulch protecting the base of the stems. Even if the above-ground parts freeze, the plant may regrow from the roots. In a continental climate, however, this risk is too great, and container cultivation remains the only reliable solution.
Uses in ornamental gardening
Passiflora coactilis is primarily a collector's and greenhouse plant, but its ornamental qualities are undeniable. Large, velvety leaves quickly cover trellises, pergolas and mesh fences, creating a dense green screen, while the drooping pink flowers with a long column look exotic and attract attention. In a conservatory, it can be trained under the roof, allowing the flowers to hang above visitors' heads. On a terrace in summer, it works well as a seasonal screen, while indoors it makes an attractive specimen in a large pot near a bright window. The fruits are an additional attraction and can also be obtained in container cultivation through hand pollination.
History, etymology and cultural significance
The species was described in the 19th century by the British botanist Maxwell T. Masters as Tacsonia coactilis, at a time when long-flowered Andean passion flowers were treated as a separate genus, Tacsonia. The American botanist Ellsworth P. Killip, author of a monumental monograph on the American Passifloraceae, transferred it to the genus Passiflora in 1924, giving it the currently accepted name Passiflora coactilis (Mast.) Killip. The synonyms include Tacsonia mariae and Passiflora mariae, described by the Jesuit Luis Sodiro, who worked in Ecuador. The specific epithet coactilis comes from Latin and means “felt-like, matted like felt” - a reference to the dense, soft hairs on the shoots and leaves. The generic name Passiflora, “passion flower”, was given by Spanish missionaries who saw symbols of the Passion of Christ in the flower’s features.
In the Andes, the fruits of tauso and related passion flowers have formed part of the local diet for centuries, and the plants are sometimes grown near homes and along fences. Today, the species interests botanists as an example of extreme coevolution between a plant and its pollinator: its flowers, with a column more than ten centimetres long, rank among the most extreme in a genus containing over five hundred species.
Who is this species for
Passiflora coactilis is suited to gardeners who already have experience growing container vines and have a bright, cool place for overwintering - a greenhouse, conservatory or unheated veranda. It will appeal to passion flower collectors, enthusiasts of Andean flora and people seeking plants with unusual flowering biology. However, it is not suitable for gardens without winter protection or for warm, dry homes lacking humidity and cool nights.
Summary
Passiflora coactilis combines very rapid growth, decorative felt-like leaves and some of the most unusual flowers in the genus with a realistic chance of producing aromatic, edible fruit. Its origin in cool cloud forests means that it tolerates light frosts and performs well in moderate temperatures, but it still requires protection from severe frost and dry heat. The species has not yet been assessed in the IUCN Red List; in its native range it is locally used, while in horticultural cultivation it remains a rare plant worthy of every collector’s attention.
