Download Rhododendron auriculatum - University of St Andrews

August 2009
Rhododendron
auriculatum
Text and Photographs by Bob Mitchell
August brings on the hot summer colours of the herbaceous plants, much beloved of butterflies. These borders
are at their best this month. But there is also an increasing number of white-flowering woody plants coming into flower
now. As I write the 15' tall Hoheria glabrata from New Zealand is laden with white, almost translucent, flowers. It
grows at the top of the Rhododendron garden near to the summer house. Later this month and into September the lovely
eucryphias will produce spires of white Hypericum-like flowers.
In the Rhododendron House there is another white
flowered shrub flowering now. This is Rhododendron edgeworthii,
with us one of the last of the Maddenia Section rhododendrons to
flower - other species produce a sequence of flowering from
January. To this selection I add one of the last rhododendrons to
flower in the Garden this summer. Augustine Henry discovered
Rhododendron auriculatum close to Ichang in 1885 and it was
named by Hemsley in the Journal of the Linnean Society in 1889.
Augustine Henry, born of Irish parents in Dundee in 1857,
studied medicine in Belfast before being appointed to the Imperial
Maritime Customs Service in China in 1880. It was when he was
resident at Ichang in Hubei Province, he started to collect
herbarium specimens for Kew. Noting the devastation of the
vegetation in the surrounding countryside he approached Kew to
send a botanist to collect in west central China. So Ernest Wilson
was sent to Ichang to start collecting seeds, plants and herbarium
specimens in 1889. Veitch Nurseries sponsored his first two
expeditions. Wilson collected fifteen different rhododendrons, from 21 collections, on his first expedition, of which ten
were introduced to cultivation for the first time. One of the fifteen was Rhododendron auriculatum, collected under
his number W. 920. Rhododendron auriculatum featured in Curtis'
Botanical Magazine in 1919. The plant received an Award of Merit
in 1922 and an Award of Garden Merit in 1984.
Rhododendron auriculatum has grown to 15' in just over 20
years and is wider than high. It is distinctive with its pointed foliage
buds. There are prominent, but transitory, showy crimson-coloured
bracts as the flowers and leaves unfold to produce 6" long, oblong
leaves which are eared (auricled) at the base. The inflorescence
can have up to 15 fragrant flowers, each up to 5" across. They are
white, with 7-8 lobes and have a pale yellow-green blotch at the
base. The style is curved and is glandular to the tip.
The equally late flowering Rhododendron 'Polar Bear' is a hybrid
with Rh. diaprepes, dating from 1933.
Cultivation.
With its late flowering this is a useful addition to a Rhododendron
collection but it does need a sheltered and shady position. A moist acid soil is necessary for successful cultivation.
Propagation.
Plants grown from seed may take 10 years to flower. Layering is an good option for low growing branches. Plants are
available from specialist nurseries.
Position.
Rhododendron auriculatum is growing at the north-west corner of the Rhododendron garden on one of the terraces.