A deciduous shrub usually 3 to 5 ft high, open in habit, and sparsely branched; branches stiff, four-angled, the angles much winged. Leaves narrow-lanceolate, 3 to 8 in. long, 1 to 2 in. wide; minutely and sparsely toothed; dark green and glabrous above, at first tawny-felted beneath. Flowers crowded densely in terminal branched panicles, 4 to 8 in. long. Corolla pale lilac, woolly outside, the tube 1⁄2 in. long; the four lobes small. Calyx woolly, pitcher-shaped, with slender-pointed lobes; both calyx and corolla are persistent on the seed-vessels, which are egg-shaped, 1⁄4 in. long, and very freely borne.
Native of Japan. This is not one of the best of the buddleias, although rather striking in autumn with the long, dense, drooping panicles of fruit. It bears these in such abundance that they appear to shorten the life of the shrub. At any rate, after a few years it becomes weak and thin in growth, and should be renewed (by seed rather than by cuttings). It has been cultivated on the continent as “B. curviflora”, but is not the true plant of that name.
B. × intermedia (Carr.) Rehd. – The original plant appeared in France among seedlings of B. japonica and is thought to be a hybrid between B. japonica and B. lindleyana.
cv. 'Insignis'. – This seedling of B.japonica is now thought to be a form of B. × intermedia. Described by Carrière in Rev. Hort., 1878, p. 330, as B. insignis (B. japonica var. insignis (Carr.) Wils.). It is of more compact habit than B. japonica, with brighter-coloured flowers.