Wollastonia subcordata is a suffruticose, woody perennial herb with erect to ascending stems that range from 30 cm to 3 meters in length. The leaves are simple and petiolate, with blades that range from narrowly deltate to broadly deltate in shape. Leaf blades measure between (2.4–)3.4–10(–16) cm in length and (2.4–)3–6(–10) cm in width and often exhibit two prominent basal lobes. The texture is thin and herbaceous, with a strigillose (finely hairy) surface, especially dense on the lower surface. Margins are typically entire or shortly serrate, and petioles are 1–3 cm long. Flower heads are arranged in compound cymes or occasionally in small clusters of 2–3. The outer involucral bracts are lanceolate to ovate, (3–)4–6 mm long and 1.5–2.3 mm wide, often showing a purple tint along the midrib. These bracts are sparsely to moderately strigillose and have an apex that ranges from attenuate to obtuse. The chaffy bracts are often tinged purple near the apex or tan throughout. Each flower head contains 5–8 ray florets with oblong rays (3–)4–6(–7) mm long and 2–4 mm wide, and 11–20(–45) disk florets, which are 2.5–3.7 mm long. Anthers are 1.1–1.5 mm long. The pappus is composed either of an uneven corona of scales tipped with short deciduous awns or solely of short awns. The fruits are tuberculate achenes, often spotted with purple and topped with a fringe of scales on the upper outer rim. Ray achenes are 1.9–2.8 mm long and 1.5–2.5 mm wide, with marginal wings approximately 0.4 mm wide, while disk achenes are 2.1–2.8 mm long and approximately 1.5 mm wide, with narrower wings if present (~0.2 mm).