Cinchona pubescens aka Quinine

Cinchona pubescens is a tropical tree known as red bark. It belongs to the Rubiaceae family. Its native range stretches from Costa Rica south to Bolivia. It also grows in Panama, Venezuela, Colombia, Ecuador and Peru. Wild trees grow in cool, damp mountain regions. Their habitat reaches about 3,280–12,140 feet [1,000–3,700 metres] above sea level. People now grow this tree in many tropical regions.

Garden size is about 33–49 feet [10–15 metres] tall. Its spread can reach 49 feet [15 metres]. One source gives a broader height range of 30–98 feet [9–30 metres]. Most accounts describe an evergreen tree, though one summary calls it deciduous. Its small branches are thick and hairy. It grows fast and can flower within two to three years. Bees and butterflies visit and pollinate the flowers.

This tree needs warmth, moist soil and good drainage. It grows in full sun or partial shade. Sandy and loamy soils suit it. It prefers acid soil, with a pH of 5–6. Sources also report tolerance of a wider soil pH range. Best growth occurs with daytime temperatures of 17–25°C. Temperatures of 5°C or below may kill it. PFAF lists USDA zones 10–12. It favours climates with heavy rain through the year. It grows poorly, or fails, in soils exposed to fire.

The bark has a long history of use against fever. It contains quinine, a drug used to treat malaria. Another bark alkaloid, quinidine, affects the heart. Heavy wild harvest followed European interest in the seventeenth century. Growers later established plantations in Java. Synthetic drugs replaced much quinine use during the twentieth century. Drug-resistant malaria later renewed its medical role. Growers can raise trees from seed and manage them by coppicing.

Quinine from the inner bark adds bitterness to tonic water. Manufacturers also use it in sweets, baked foods and liqueurs. Other uses include shampoo, hair oil and insecticides. Industry uses it in rubber processing and some metal preparation. These uses do not make raw bark safe to consume. Excessive medicinal use can cause headache, rash and stomach pain. Serious effects include loss of hearing and sight. PFAF also flags this tree as having weed potential. The supplied accounts give no specific pest or disease problems.