Stems (10-)35-70(-85) cm; base often reddish, puberulent. Leaves basal and cauline; basal leaves 0-4 at anthesis; cauline leaves 3-7(-10) at anthesis; petiole 0.5-11 cm. Leaf blade round, 1.5-5 × 3-9 cm, puberulent; ultimate lobes 5-18, width 2-15 mm (basal), 1-10 mm (cauline), widest at middle or in proximal 1/2. Inflorescences 3-15(-43)-flowered; pedicel 1.5-4(-7) cm, (glandular) puberulent; bracteoles 8-10(-24) mm from flowers, green to blue, linear, 4-6(-9) mm, puberulent. Flowers: sepals bluish purple or yellowish, often partly fading upon drying, puberulent, lateral sepals spreading, (11-)13-20 × 5-11 mm, spurs straight, ascending less than 30° above horizontal, 11-17 mm; lower petal blades ± covering stamens, 8-12 mm, clefts 0.2-2.5 mm; hairs sparse, centered, mostly near junction of blade and claw above base of cleft, white or blue. Fruits 11-17 mm, 3.5-4 times longer than wide, puberulent. Seeds wing-margined; seed coat cell surfaces smooth, without swollen blunt hair.

Although Delphinium menziesii has often been confused with D . nuttallii , it may be distinguished by its consistently larger flowers and usually fewer flowers per plant. Interestingly, each species produces both blue-purple and yellowish flower colors in separate populations.

The Chehalis consider Delphinium menziesii poisonous, but they also apply it to sores. The women of the Thompson Indians use it as a love charm (D. E. Moerman 1986, subspecies not indicated).