[1] It is native to California and the Northwestern United States in Oregon, Idaho, and Washington, and north into British Columbia, Canada.

Trichostema oblongum is an annual herb approaching fifty centimeters (20 in) in maximum height.

Its aromatic foliage is coated in glandular and nonglandular hairs.

The inflorescence is a series of clusters of flowers located at each leaf pair.

Each flower has a hairy calyx of pointed sepals and a tubular, lipped purple corolla.