Cyrtandra garnotiana is a shrub growing 1–4 meters tall. The stems are rounded to angular and pubescent with multicellular hairs or glabrate. The leaves are simple and opposite, borne on the upper 3–6 nodes. Leaves in a pair are unequal to subequal, asymmetrical, broadly elliptic, elliptic, or ovate, measuring (6.8–)10–25(–36) cm long and 5–10(–14) cm wide. The apex is acute to acuminate, and the base is cuneate to attenuate. The upper surfaces are sparsely hirtellous, while the lower surfaces are moderate to densely velvety short–pilose, sometimes restricted to veins. Blades are chartaceous, and margins are serrate or serrulate. Petioles are (1.7–)3–8(–11.5) cm long, sometimes clasping the stem or perfoliate at the base. Stipules are absent. The flowers are bisexual (perfect) and occur in groups of 3–12 in branched cymes arising in the leaf axils. The cymes are short–pilose throughout, with stout peduncles measuring (15–)25–82 mm long. Pedicels are 10–18 mm long, elongating to 15–25(–32) mm in fruit. Bracts are narrowly lanceolate or occasionally oblanceolate, foliaceous, and distinct or occasionally connate, measuring (4–)7–15 mm long. The calyx is nearly actinomorphic (radially symmetric), 2–5(6)-lobed, greenish-white to white, measuring 6–10(–14) mm long and cleft halfway, with some lobes slightly longer. The lobes are narrowly deltate to narrowly ovate, densely short–pilose, and deciduous or persistent in fruit. The corolla is bilabiate and white, with a subcylindrical tube slightly flaring at the mouth, measuring 7–14 mm long. The upper lip is 2-lobed, and the lower lip is 3-lobed. Lobes are reniform to orbicular, with upper lobes measuring 1–2.5 mm long and ca. 4 mm wide and lower lobes ca. 3–4 mm long and ca. 3.5–5 mm wide. There are five stamens, of which the two upper ones are fertile, positioned in the throat of the corolla tube. The ovary is superior, oblong–ovoid, 1-celled with parietal placentation, and the style is 0.5–2.5 mm long with a capitate, 2-lobed stigma. The fruit is a fleshy or firm berry, white, ovoid, 1.2–1.7 cm long, and puberulent, often tipped by a persistent stylar beak. The seeds are numerous, ellipsoid, minute (0.3–0.4 mm long), and reticulate. It is found in moist, shaded gulch bottoms, slopes in disturbed mesic valleys, and occasionally in wet forests between (180–)300–850 meters.