A shrub 3 to 5 ft high; young shoots glabrous except for two downy ridges. Leaves 2 or 3 in. long, 1 to 11⁄2 in. wide, ovate-lanceolate, toothed, wrinkled, slightly hairy on the margins and on the chief veins when young only; stalk 1⁄6 in. or less long. Flowers in terminal cymose clusters. Corolla bell-shaped, sulphur-yellow, stained with orange on the lower lobes, 11⁄4 in. long, 1 in. wide across the mouth, where are five spreading lobes. Calyx two-lipped, the upper lip with three narrow lobes, the lower one with two broader, deeper ones, all fringed with short bristles. Flowers in April and May. Bot. Mag., t. 7876.
Native of Japan, N. China, Korea and the Russian Far East; introduced to Europe in 1850. A beautiful shrub, very distinct in its yellow blossoms. But it suffers much from late spring frosts in some gardens.
It is the only species of the section Calyptrostigma. Apart from its yellow flowers, its distinctive characters are the two-lipped calyx, the hooded (calyptrate) stigma and the connate anthers.
Another yellow-flowered, anomalous species is W. maximowiczii (S. Moore) Rehd., which is similar to W. middendorffiana in most of its botanical characters, but inferior to it as an ornamental. Native of Japan.