Eranthemum pulchellum comes from India, Himalaya and West China. Its name means 'lovely flower' and its panicles of rich or paler blue blooms are indeed very pretty when they appear in late winter and early spring. Sometimes known as the blue sage bush, it grows into a shrub about 1 m tall and is most useful for a shaded part of the garden, where other plants may struggle. It has attractive veined leaves. I have seen it paired very effectively with the beetroot-coloured leaves of Iresine herbstii 'Brilliantissima' in a shady garden spot. I also like it grown nearby cream Clivia miniata and pale blue Iris japonica or Iris wattii, which have lovely blooms of the same hue as the Eranthemum at the same time, and enjoy a shaded spot in the garden. I also like to pair Eranthemum with the shade-tolerant annual honesty, which flowers at the same time and has similar simple, open flowers, which are white or purple.
Like most plants in the family Acanthaceae, it needs to be cut back hard after flowering or it will become very straggly. Compared to many other Acanthaceae plants, the flowering period is relatively short, but it is very attractive when in bloom.The flowers do have a tendency to stay on the shrub after they have withered, which is a shame. They can be flicked off to give a better look - if you have time! I feel this shrub is better placed towards the back of a border rather than right at the front, so it can disappear into the background when it is not in flower. In England, this plant is grown in a pot in a greenhouse. There is apparently a species with rose-coloured flowers, called Eranthemum roseum, but I have yet to set eyes on it. In recent times, I have been given a variant that has much deeper blue flowers than the usual form (pictured above), which is very appealing when in bloom. In my garden, it flowers a few weeks earlier than the pale blue version and seems a more open, slightly gawky shape. Possibly it is a different species: Eranthemum wattii.