The blood of R. arboreum - packed in brown sugar
Rhododendron arboreum, which grows to 90 feet in the Himalayas, is the ancestor of hundreds of hybrids.
Driving through Portland, Oregon, during the last three weeks, you couldn't help but notice the pink dogwoods, towering green and white clouds of blossoming chestnut trees and the red rhododendrons.
Hugh Johnson writes in his book of trees -
Until 1820 the European and American rhododendrons were the only ones known. Of these the rosebay rhododendron, R. maximum, from the eastern States, was the biggest - though scarcely a tree.
In 1820 the first seeds of R. arboreum arrived in England from the Himalayas, packed by the prudent Nathaniel Wallich in brown sugar. With them arrived the glorious red blood that transformed the relatively tame and dowdy colours of the rhododendrons then known. For though R. arboreum was tender at first, and needed a conservatory in Britain, it soon hybridized and started hardy strains. Waterers, the famous nurserymen of Surrey, were the pioneers in adapting this tender giant to cultivation. Most modern rhododendron varieties, even small ones, have the blood of R. arboreum in their veins.
Sir Joseph Hooker's expedition to the Himalayas from 1847 to 1850 set the seal on the rhododendron as the supreme flowering evergreen. He introduced 43 species, including the tree-size R. falconeri.
Here I see a fine collaboration between a Dane and Brits (Wallich was Danish).
Sir Charles Lemon took some of the seeds brought back by Joseph Hooker and bred R. arboreum 'Sir Charles Lemon', which has white blossoms and red-brown felt on the undersides of its leaves.
Those fellows were adventurous and patient.