Rhododendron arboreum

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Local names:
English (rose tree,rhododendron), Nepali (lali gurans), Trade name (chalan)

Rhododendron arboreum is one of the most stately and impressive rhododendron species. It is extremely variable in stature, hardiness, flower color and leaf characteristics. Originally discovered in north-central India, the plant known locally as Lali Guras is the tallest of Nepal’s rhododendrons, reaching heights of more than 20m. It has the largest trunk and flowers, blossoming earlier and longer than the others. 
 In its native land, huge trees of R. arboreum grow to a height of 25m or more.
Trunk often much branched, crooked or gnarled. Bark reddish brown, soft and rough, exfoliating in thin flakes.
 
The foliage of R. arboreum is extremely handsome. Its thick, stiff, leathery dark green leaves are covered on the under surface with a thin layer of indumentum ranging in color from silver to fawn to deep cinnamon, elegant in foliage. Leaves glossy green, oblong-lanceolate, 10-20 cm long and 3.6 cm wide. Crowded towards the ends of branches, petiole covered with white scales when young.

The flowers of R. arboreum range in color from a deep scarlet, to red with white markings, to pink to white. Bearing up to twenty blossoms in a single truss this rhododendron is a spectacular sight when in full bloom. It is reported that the bright red forms of this rhododendron are generally found at the lower elevations.

Fruit a capsule, oblong, curved, longitudinally ribbed, up to 3.8 cm long and 1.25 cm wide.

Seeds minute, dark brown, compressed, oblong.

Three varieties are recognized, var. cinnamomum is a small tree with smaller leaves and white, pale rose or purple spotted flowers and occurs in Nepal and northern Bengal.

R. arboreum in the world’s most famous rhododendron. This spectacular plant was designated the national flower of Nepal, the legendary home of Mt. Everest and other mountain gods. It’s even depicted on the national coat of arms.

Ecology

R. arboreum is found in many vegetation types, and sometimes forms almost pure forest in restricted areas. It is common in the western Himalayas in association with Quercus species and Pinus roxburghii. It thrives best on moist loam although it is also found on moist rocky ground. The tree can withstand shading although it develops better in the open.

Native range
Bhutan, China, India, Nepal, Pakistan

Tree management

It coppices well but is a slow growing tree.

There are about 12 million seeds/kg. They are extracted by drying the capsules on paper in the sun.

R. arboreum is found in many vegetation types, and sometimes forms almost pure forest in restricted areas. It is common in the western Himalayas in association with Quercus species and Pinus roxburghii. It thrives best on moist loam although it is also found on moist rocky ground. The tree can withstand shading although it develops better in the open.

R. arboreum can be raised from seed although propagation is mainly through cuttings and wildings. Seedlings can be raised artificially in containers filled with fine sand; the seed should not be covered. They are pricked out at the 2-leaf stage. Young seedlings should be kept under shade.  Seeds are best sown in a greenhouse as soon as it is ripe in the autumn and given artificial light. Alternatively sow the seed in a lightly shaded part of the warm greenhouse in late winter or in a cold greenhouse in April.

R. arboreum readily colonizes newly disturbed ground such as road cuttings and landslides and in the crevices of bare rocks.

  Flowers are sour-sweet and are eaten as pickles, although excess may cause intoxication. A sub-acidic jelly or preserve is made from the petals. The  flower petals are eaten raw as a famine food in India.

The wood is used as fuel and for making charcoal.

Timber:  Sapwood reddish to brownish white; heartwood reddish brown, moderately hard, 640 kg/cu. m. It is easy to work, finishing to a smooth surface. It is used for tool handles, boxes and posts and is suitable for plywood.

Medicine: Leaves are applied to the forehead to relieve headache. Unspecified parts are used in the treatment of diarrhoea and dysentery.

Ornamental:  R. arboreum (Lali Guras in Nepal) is distributed throughout the length of Nepal at a variety of altitudes. It is known for its variably colored blossoms, which come in shades of red, pink and white. The blossoming plants are a spectacular sight, with up to twenty blossoms in a single truss. 

Other services: The foliage adds to the plant’s beauty. The under surface of the thick, stiff, leathery dark green leaves are covered with a thin layer of indumentum ranging in color from silver to fawn to deep cinnamon. Certain areas are known for their