The calyces of mertensia franciscana
are quite distinctive; they are dark green in color, divided into five narrowly lanceolate lobes, and their margins and (less densely) faces are covered with relatively long, spreading white hairs. Flower stalks are similar in color and hairiness. The pendant flowers are pink to purple when in bud and blue when fully open, withering to darker blue and then brown. The corolla lobes are shorter than the tube.
Leaves have a center vein, a pair of fainter side veins branching from the base, and other side veins higher up. The upper leaf surfaces are usually finely strigose hairy, while the lower surfaces have a generally denser hair covering, though may sometimes be hairless. Stem and leaves are hairy. Stem leaves are mostly sessile but those near the base may have short stalks. Plants typically produce several stems, ascending to erect.