The species name of phacelia bicolor refers to the color of the bell- or funnel-shaped corolla; the tube is yellow while the five rounded lobes are purple, withering to blue. The yellow part is crossed by thin, lengthwise, purple veins. The corolla may be up to 0.7 inches long, about twice the length of the calyx, which is divided into five linear, equally-sized lobes, glandular hairy on the outside. The finely hairy stamens are included within the tube, and are similar in length to the calyx lobes; they have pale yellow filaments and darker yellow anthers.

Stems may grow vertically upwards or lean over, and they branch from the base. They, and the dark green leaves, have a covering of short, spreading hairs, slightly glandular. Leaves are compound, divided into irregularly lobed leaflets, and are similar in size at the base and along the stem. The leaves generally rise a little way above the inflorescence.

Phacelia fremontii is a very similar species, though found in different regions; this has hairless stamens, less divided leaves, and flowers held well above the leaves.