Shrubs, 0.4-1.5(-3) m tall; branches arching to spreading, slender, often rather lanky. Stems 4-lined and ancipitous when very young, soon not ancipitous, sometimes becoming 2-lined or terete; internodes 1-4 cm, shorter than leaves. Leaves with petiole 1-1.5(-2) mm; blade narrowly elliptic or rarely lanceolate or lanceolate-elliptic to ± broadly oblong-elliptic or (on strong central shoots) ovate-elliptic to broadly oblong-ovate or broadly triangular-ovate, 1.8-5 × 0.6-4.5 cm, thickly papery, abaxially ± glaucous; laminar glands dots and very short streaks; abaxial glands dense to absent; main lateral veins 2-4-paired, tertiary reticulation lax, not or scarcely visible; base cuneate, apex acute or apiculate-obtuse to rounded. Inflorescence 1-10(-15)-flowered, from apical node, ± flat-topped; bracts reduced and narrowly elliptic to linear or leaflike, persistent. Pedicels 2-10 mm (to 1.5 cm in fruit). Flowers 3-5 cm in diam., substellate to shallowly cupped; buds narrowly to broadly ovoid, apex acute or apiculate to obtuse. Sepals erect or suberect in bud, suberect or outcurved in fruit, equal to subequal, sometimes leaflike, narrowly lanceolate to oblong-ovate or ovate, (6-)7-10 × 3-5.5 mm (enlarging in fruit to ca. 1.1 × 0.7 cm); laminar glands lines, sometimes distally interrupted; margin entire or apically minutely and ± irregularly denticulate, apex acute to obtuse. Petals golden yellow, narrowly to rather broadly obovate, 1.8-2.4 × 1-1.5(-1.8) cm, 2.5-3 × as long as sepals; margin entire or minutely glandular-denticulate; apiculus rounded or obsolete. Stamen fascicles each with 40-50 stamens, longest 1.2-1.8 cm, 0.6-0.7 × as long as petals. Ovary narrowly ovoid-conic to broadly ovoid, 5-8 × 3-5 mm; styles 4-7 mm, 0.5-0.7(-0.85) × as long as ovary, free, suberect to divergent, outcurved near apex. Capsule ovoid-conic to ovoid, 1-1.7 × 0.7-1.2 cm, shallowly 5-lobed. Seeds purplish brown, ca. 1.4 mm, shallowly carinate; testa linear-reticulate. Fl. Apr-Aug, fr. Jun-Nov.

Hypericum lagarocladum has a spreading habit, at least when young; and even if it grows taller later on, the ends of the arching branches tend to be lanky. It exhibits a SE-NW trend in variation, the Hunan and Guizhou plants having a more erect habit and narrower leaves and sepals, while in those from Sichuan and most of Yunnan the habit is spreading and the leaves and sepals are broader. Apart from a small area of overlap in variation in SW Sichuan and extreme NW Yunnan, the two ends of the trend seem to remain distinct and can be regarded as subspecies.

● Thickets on slopes or in valleys, streamsides, roadsides; (400-) 1500-2700 m. Guizhou, W Hunan, S and W Sichuan, NE Yunnan.