Enkianthus is a genus of about 10 species of mainly deciduous shrubs occurring in woodland from the Himalayas to Japan. Enkianthus campanulatus is the species primarily used for bonsai cultivation, growing to around 5 metres in its native habitat. E. campanulatas has opposite dull green leaves up to 6cm long that turn to vivid orange-yellow and then red in the Autumn. It is especially favoured for its racemes of between 5-15 bell-shaped creamy-yellow flowers which appear in late Spring and early Summer. There are two commonly available varieties; ‘albiflorus’ which carries white flowers and ‘Hiraethlyn’ which has cream flowers with dark-red veins.
There are other Enkianthus species that have bonsai potential; E. perulatus is more compact and has smaller leaves so is more suitable for smaller sized bonsai. E. cernus var.rubens has slightly toothed leaves up to 5cm long that turn a dark purple-red in Autumn, it carries rich red flowers.
Enkianthus are lime-hating (as with Rhododendrons and Azaleas) and lime/alkaline soils should be avoided.
BONSAI CULTIVATION NOTES
POSITION: Full sun in Spring and Autumn, slight shade in summer. Frost hardy to at least -5°C.
FEEDING: Feed a balanced feed fortnightly after flowering, occasional replacement feed with an ericaceous fertiliser is necessary and will balance out the soil PH.
REPOTTING: Annually in spring as buds extend, use a standard mix but ensure that any grit or stone used as part of the soil mix is well washed to ensure the removal of any lime.
PRUNING: Trim back new shoots to shape through the growing season after flowering has finished. Hard pruning can be carried out after flowering. Large scars are slow to heal.
PROPAGATION: Sow seed at 18-21°C in late winter or early spring. Take semi-ripe cuttings in summer. Air-layer in late Spring or ground-layer in Autumn for removal the following Spring.
PESTS AND DISEASES: Trouble free though yellowing leaves can indicate chlorosis due to the presence of lime.
STYLING: Informal upright forms with single or multiple trunks in small to large sizes.