Stems 20-80cm tall, slender and rather brittle. Leaves opposite, all cauline, sharply toothed. Inflorescence a panicle.
Flowers bright lavender, 2.2-3.2cm long. Cliff crevices and other dry, open mostly rocky places at lower elevations; east of the Cascade summits and in the Columbia River Gorge in Washington and Oregon, extending into British Columbia. Three varieties. Pendulous habit suitable for walls and hanging over a rock on sunny sheltered sites. Exceptional for its late season of bloom. Easily grown.