Blue Eranthemum is an evergreen shrub native to India and the Himalayan region, and now widely cultivated as an ornamental plant in southern China. Its flowers are in stunning purplish-blue colour, with light green bracts that resemble young leaves. Besides being an important winter nectariferous plant, it serves as a larval food plant for Lemon Pansy, Chocolate Pansy and Common Spotted Flat. In particular, Common Spotted Flat caterpillars create sleeping bag-shaped leaf shelters with Blue Eranthemum's leaves to avoid predation.