Meriania nobilis - Colombian Meriania
Meriania nobilis is one of the most spectacular flowering trees of the Colombian Andes and also one of the most magnificent representatives of the Melastomataceae family. In Colombia, it is known as amarrabollo, amarraboyo or flor de cera - "wax flower" - names that refer to its thick, fleshy petals with an unusual, seemingly waxed texture. Horticultural literature also uses the names motley meriania and manacá colombiano. The species was described in 1871 by the Colombian botanist José Jerónimo Triana, and its Latin epithet nobilis, meaning "noble", directly refers to the beauty of its flowers, considered among the most beautiful in the entire family.
Outside Colombia, the plant remains little known. In Europe, it appears only in botanical collections and among enthusiasts of Andean flora, although its requirements - a cool, humid, frost-free climate - make it an interesting candidate for greenhouse cultivation. The following article compiles available botanical information and practical tips for those who wish to grow this species in a temperate climate.
Botanical description and plant habit
Meriania nobilis is an evergreen tree reaching 5-15 m in height, although 11-15 m is most commonly reported under natural conditions, and its trunk can reach 30 cm in diameter. The bark is flaky, while young branches have a characteristic square, distinctly winged cross-section and a purple colour; with age, they become more rounded and smooth. This shoot structure is typical of many Melastomataceae and helps identify the plant even without flowers.
The leaves are simple, opposite, and elliptic, 20-30 cm long and about 12 cm wide. The leaf blade is thick and leathery, dark green and glossy on the upper surface, and purple or reddish underneath, creating an eye-catching contrast when the wind lifts the branches. The margin is finely toothed, while the venation - as in the entire family - is arcuate, with several main veins running parallel from the base towards the tip. The root system is shallow and not very extensive, so the tree does not damage pavements or foundations, a feature appreciated when planting in urban areas.
Growth rate and development
For a tree from humid mountain forests, Meriania nobilis grows quickly. Nursery sources report that seedlings can reach about 2 m in height within two years if provided with warmth, moisture and fertile substrate. The plant forms a branched, dense crown early and can be maintained as a 1.5-3 m shrub with regular pruning. In the ground, in a frost-free climate, it reaches its full size within a dozen or so years and is a long-lived tree, planted in Colombia as part of permanent urban greenery.
In a temperate climate, growth is clearly seasonal: during the warm and humid summer period, the plant produces new leaves intensively, whereas in a cool winter room, growth almost stops. This is worth bearing in mind when planning repotting - it is best done in spring, before the main growth begins.
Flowering and propagation
The flowers are what attract the attention of botanists and gardeners to this species. Collected in terminal panicles, they reach 7–8 cm in diameter and consist of five thick, waxy petals ranging in colour from violet to purplish-red; in Colombia, forms with dark violet flowers and lighter, pinkish ones are distinguished. The centre of the flower is occupied by numerous magenta stamens ending in large, bright yellow anthers that open through pores at the top - a mechanism typical of the Melastomataceae, known as buzz pollination. Pollen is released only when an insect makes the anthers vibrate at the right frequency; in nature, this is done primarily by bumblebees of the species Bombus pauloensis. Bees and hummingbirds also visit the flowers, and the species is considered a valuable honey plant.
In its native range, flowering occurs in waves throughout the year, without a distinct dormant period. After pollination, elongated capsules develop; as they mature, they turn brown or purple and release very numerous, tiny seeds. The fruits are sometimes eaten by insects, birds and, locally, people. In cultivation, the plant is propagated mainly from seed; stem cuttings root with greater difficulty and require high humidity.
Environmental requirements and tolerance
The key to understanding the needs of Meriania nobilis is its natural habitat. The species is endemic to the Colombian Andes - the Central and Western Cordilleras - and grows at elevations of 1900–2900 m above sea level in humid cloud forests. The climate there is cool and stable, without frost or heatwaves: temperatures throughout the year usually range from 10–24°C, air humidity is very high, and frequent fog and rainfall keep the soil constantly moist. The tree grows in the understorey or along forest edges, in deep, fertile, humus-rich, acidic soils.
This results in the following tolerance profile: the plant cannot withstand frost and is sensitive even to brief temperature drops below 0°C, which is why its minimum hardiness zone is classified as USDA 10. It also responds poorly to prolonged heat above 30°C combined with dry air, which causes leaf margins to scorch. It tolerates a wide range of light levels - from partial shade to full sun - provided that the substrate remains moist and humidity is high. It tolerates pruning and repotting well.
Cultivation in a temperate climate
In cooler regions of Europe, Meriania nobilis is grown as a container plant. The best location is a bright orangery, conservatory or spacious room with an east- or west-facing window. From late spring to early autumn, when nighttime temperatures do not fall below 8–10°C, the plant can be placed on a wind-sheltered terrace or in the garden in partial shade; gradually acclimatize it to sunlight. For winter, move it to a bright, cool room with a temperature of 8–15°C - these conditions mimic cool Andean nights and allow the plant to rest without losing its leaves.
The substrate should be well-drained, rich in humus and slightly acidic (pH 5.5–6.5). A mixture of coconut fiber or peat with mature compost, perlite and fine pine bark works well; a thick drainage layer at the bottom of the pot is essential, as the shallow roots easily rot in stagnant water. Water with soft, preferably rainwater when the top layer of soil begins to dry, and never allow the root ball to dry out completely. Provide high humidity with a humidifier, misting or by placing the pot on a tray filled with wet expanded clay. Fertilize during the growing season every 3–4 weeks with diluted liquid fertilizer, preferably one formulated for acidic conditions. Carry out formative pruning at the end of winter or just after flowering, removing weak and crossing shoots and shortening excessively long growth.
In regions with a mild, humid oceanic climate, such as the Atlantic coasts of the Iberian Peninsula, the Canary Islands or Madeira, the species can be grown in the ground in sheltered locations. There, choose a spot in the partial shade of taller trees, with deep, fertile soil, and mulch the surface to retain moisture. Protect young plants from cold winds and unexpected frosts during their first years.
Uses in ornamental horticulture
In Colombia, Meriania nobilis is one of the most popular native ornamental trees: it is planted along the streets of Medellín, in parks and gardens, and in mountain forest restoration programs, where it is valued for its rapid growth, minimally invasive roots and benefits to pollinating insects. Gardeners value it for three features at once: showy, long-lasting flowers, decorative large leaves with two-toned blades and a compact, regular crown. In Europe, it is a collector's plant - in a large pot, it forms an impressive conservatory specimen that brings a tropical character indoors even when not in bloom. It combines well with other cloud forest plants, such as fuchsias, shrub begonias, tibouchinas and tree ferns.
Cultural significance, history and etymology of the name
The genus name Meriania commemorates Maria Sibylla Merian (1647–1717), a German naturalist and illustrator, author of the famous work on the insects of Suriname and one of the first women to conduct natural history research independently in the tropics. The genus includes approximately 90–100 species of trees and shrubs distributed from Mexico to Brazil and the Antilles, with a center of diversity in the Andes. Meriania nobilis, described by Triana in the Transactions of the Linnean Society in 1871, is the best-known species in cultivation among them.
The Colombian name amarrabollo (from amarrar – to tie, and bollo – bun, parcel) probably refers to the former use of the large, leathery leaves for wrapping and tying corn dough dishes. In recent years, the species has also attracted the interest of natural-products researchers: numerous hydrolysable tannins and phenolic compounds have been detected in its leaves and are being studied for their antioxidant properties. The tree has become an informal symbol of urban greenery in Medellín, where its purple flowers adorn the streets for much of the year.
Who this species is for
Meriania nobilis is suited to gardeners with a bright, cool wintering space – a conservatory, winter garden or large, unheated room – who can maintain high humidity. It is not a plant for beginners expecting a low-maintenance specimen: it requires regular watering, monitoring and protection from extreme temperatures. In return, it offers an exotic growth habit, exceptional flowers and the satisfaction of growing a species that is practically unavailable in European nurseries. It will be particularly interesting to collectors of the Melastomataceae family, enthusiasts of Andean plants and people gardening in mild oceanic climates.
Summary
Meriania nobilis combines showy, waxy flowers in shades of violet and purple with large, bicoloured leaves and relatively fast growth. As an endemic species of the cool cloud forests of the Andes, it needs moisture, filtered light and protection from frost and heat; in temperate climates, it grows best in a container overwintered in a bright, cool place. In Colombian flora databases, the species is listed as not threatened (Least Concern, LC) and is widely planted in native forest restoration programmes, making it a good example of a species whose cultivation supports interest in the native flora of the Andes rather than depleting it.
