Rhododendron arboreum subsp. arboreum

An historic and majestic species!  Rhododendron arboreum grows in the mountains of Nepal where it is a tree that can reach over 20 m (66ft) in height.  Discovered by Captain Hardwick in 1796, it is the very first Himalayan rhododendron to have been introduced to England in 1811...

Rhododendron arboreum forms a large bush with a habit as wide as it is tall, it reasonably reaches 1.50 to 2 m in all directions in our latitudes. Some of the oldest known specimens, in England, currently measure a whopping 9 metres (29 feet). It bears evergreen leaves with a lancet-shaped, relatively narrow and pendulous form, of a beautiful dark green colour with a healthy appearance, with a white indumentum covering the underside. The central vein is deeply impressed in relief on the lamina. Each leaf persists for 2 to 3 years on the plant. The branches that bear them have a beautiful bark of garnet colour.

The flowering occurs between March and May. It is very generous once the plant is well acclimated to its location, but unfortunately it can suffer from frost due to its early flowering. The flowers are tubular campanulate, which means they have an elongated bell shape. They measure about 5 cm (2in) wide and are densely grouped in 20 to 30 copies on each inflorescence. They have a lovely cherry red colour with darker spots in the centre.

Native to the temperate lower altitude Himalayan mountains, this red form of Rhododendron arboreum is hardy down to -10°C. It appreciates a bright location sheltered from direct sunlight and cold, drying winds. This acid-loving heathland bush requires a damp and well-drained soil, rich in humus, with a low pH. A sloping situation will remind it of its original mountains and will ensure the necessary good drainage for its dense and shallow roots.

A botanical species of exception, and a symbol of Nepal, Rhododendron arboreum has given rise to numerous hybrids and will find its rightful place in a collection within a garden with a predominantly Atlantic climate.