Plant of the Week 18/4/2010: Strobilanthes dyerianus

(Acanthaceae) Common name: Persian Shield.

Culture: Strobilanthes dyerianus are a tropical sub-shrub from Myanmar (zones 9 - 10). Strobilanthes dyerianus distinctive leaf colouration gives this sub-shrub a metallic silver iridescence. Persian Shield grow almost a metre tall with a similar spread. When established, they can withstand short periods of drying out in Spring and Autum but as plant from the tropics, in Summer they will quickly collapse from heat stress if they are not kept moist. Strobilanthes dyerianus do not tolerate frost.

Position: Direct sunlight will strip the colour from Strobilanthes dyerianus leaves. As such, dappled shade during summer and full sun in winter (perhaps underneath a deciduous tree) will provide the ideal conditions for keeping them happy and looking their best. Ensure they are well protected from frost and cold air currents. Adequate moisture throughout summer is a must as the leaves will wilt quickly on hot summer days.

Flowers: Flowers are insignificant, Strobilanthes dyerianus is grown for its unique and spectacular foliage colours. 15cm stem cuttings can be taken in Autumn, strip lower leaves and cut the remaining leaf by 2-thirds to mitigate transpiration. Grow cuttings in propagating mix in a warm, sheltered position over winter.

Care: Strobilanthes dyerianus should be grown in a free-draining, moist loam soil that has been enriched with compost.

Propagation: The easiest method of propagating Strobilanthes dyerianus is by layering during the warmer months. Ensure at least 2 nodes are buried and keep the layering soil moist but not wet.