The five lobed corolla of penstemon virgatus
is colored pale purple (occasionally all-white), streaked by dark purple lines; one down the center of each lobe and others in between, within the flower center. The corolla, the short green bracts and the upwards pointing stems are all usually hairless, and not glandular. All stamens are white; the staminode is straight, a little broader at the tip and not projecting beyond the mouth of the corolla, while the other four are curved inwards. None have any hairs. Leaves are thin and relatively long, sometimes bent upwards at either side along the axis. The species is somewhat variable, in such aspects as flower size, shape of the lobes, leaf width and amount of hair.