Eranthemum pulchellum, the blue eranthemum or blue sage, is a species of flowering plant in the acanthus family Acanthaceae, native to the Himalayas, western China, India and Nepal.^[1] A strongly branched evergreen shrub, it is popular with gardeners because of the spikes of flowers that are bright gentian blue – an unusual color in the tropics.^[2] The flowers appear from green-and-white veined bracts that remain after the blooms fall, forming a column several centimetres long. The hairy leaves are large and dark green. A sprawling shrub which may reach a metre or more in height, E. pulchellum is usually kept lower and bushier through pruning. Light shade is preferred in a garden; in a greenhouse it needs warm conditions. It is easily propagated from cuttings.

The Latin specific epithet pulchellum means "beautiful".^[3]

In the UK this plant has gained the Royal Horticultural Society's Award of Garden Merit.^[4]