Shaw's Agave is a very slow-growing, small-to-medium sized agave, with green ovate leaves 20–50 cm long and 8–20 cm wide, and a variable pattern of marginal teeth. When it blooms at the end of its life, the large, clubby inflorescence forms a panicle 2–4 meters in height, whose 8–14 lateral umbels are subtended by large purple bracts. Each umbel consists of a mass of yellowish or reddish flowers.
It generally flowers February to May, and as typical for agaves, the rosette dies thereafter. Although capable of reproducing by suckering, populations vary considerably in their behavior, with some consisting entirely of individual rosettes, while others form groups or colonies of clones.