A deciduous shrub 2 to 3 ft high, of bushy habit; young shoots erect, clothed at first with a fine, close, grey down. Leaves opposite, linear or linear-lanceolate, not lobed or toothed; 1 to 13⁄4 in. long, 1⁄8 to 3⁄8 in. wide; greyish green, with a close, very minute down on both surfaces, more especially beneath. Flowers produced during July and August in cymes from the uppermost leaf-axils of the summer shoots. Each cyme is about 11⁄2 in. long, slender-stalked, and carries six to nine flowers; the upper part of the stem thus becomes a kind of slender panicle sometimes 18 in. long. Each flower is about 1⁄2 in. long, with the large lobe (or 'lip') of the corolla much fringed, blue; calyx pale blue with five awl-shaped lobes; stamens (in two unequal pairs) similarly coloured, standing out 1⁄4 in. beyond the corolla. Bot. Mag., t. 9219.
Native of Mongolia and N. China. It flowered in France as long ago as 1844 and has been re-introduced on several occasions since then. This handsome species does not appear to be long-lived in this country. In its native habitat it experiences very cold winters but these are followed by summers much hotter than ours and, like many species from such regions, it does not take kindly to our softer, more equable climate. This, at any rate, would seem to be the reason why it has proved a failure in gardens where many genuinely tender plants thrive. It grew well for a time at Rowallane in Co. Down, as recorded in previous editions, but this plant died and the Hon. Mrs O'Neil tells us that it must be many years since the species has been cultivated there. It has been grown successfully in the Cambridge Botanic Garden, however, and it is, perhaps, in that part of England, and in E. Anglia, that it is likely to succeed best. This is true of many plants from more arid and more extreme climates than ours.
The typical form is distinct from all the other cultivated species in its toothless leaves, but in the var. serrata Maxim., they are sparsely and irregularly toothed. Still, both it and the type are readily distinguished by the narrowness of the leaves.