H. echioides may grow up to 90 cm (35 in) tall, with a thick, furrowed stem and spreading branches. The leaves are 10–20 cm (4–8 in) long, oblanceolate with a short petiole. The leaves, branches and stem are all covered in thick bristles. The inflorescences are 2–3.5 cm (0.8–1.4 in) wide and subtended by between 3 and 5 large ovate-cordate involucral bracts.These large bracts are the defining feature of the genus Helminthotheca.
A number of infraspecific taxa are recognised, varying in their leaf shape.