A dwarf, much-branched, stiff, spiny shrub under 1 ft high in this country. The branches are erect, sharp-pointed, and in shape like small bodkins. They have very few leaves, and these are scarcely noticeable, being 1⁄4 to 1⁄2 in. long, very narrow. Flowers borne two to four together on a short stalk just below the apex of the branchlet; they are 1⁄2 to 3⁄4 in. long, with purplish-blue petals, and a peculiarly large, membranous, silky calyx two-thirds the length of the flower. Pod oblong, 3⁄4 in. long, glandular-hairy, usually two- or three-, sometimes four- to six-seeded. Flowers in April and May.
Native of Spain and N. Africa. It was in gardens by 1759, but still remains one of the rarer of hardy plants. The distinct colour of its flowers, more blue than those of any other hardy leguminous shrub, should have gained it more notice. It is, however, very slow-growing, and misses the sunlight of its native mountains. In the vicarage garden at Bitton it formed low dense tufts of spiny stems, occasionally perfecting seed. At the foot of a sunny wall in the Cambridge Botanic Garden it also flowers admirably and it is, perhaps, in gardens with a similar soil and climate that it is most likely to thrive. It can be propagated by cuttings or layers, occasionally by seed. It is said to grow so plentifully on some of the mountains of Spain that horses can scarcely make their way through it. Suitable for a sunny nook in the rock garden. It thrives and seeds itself at Belhaven House, E. Lothian.