Description from Flora of China
Itea arisanensis Hayata; I. arisanensis var. longifolia Yamamoto; I. arisanensis var. parvifolia Yamamoto; I. chinensis Hooker & Arnott var. arisanensis (Hayata) Masamune; I. parviflora var. arisanensis (Hayata) H. L. Li; I. parviflora var. latifolia H. L. Li.
Shrubs or small trees, evergreen, to 5 m tall. Branchlets slender, glabrous or glabrescent. Petiole slender, 1-1.5 cm; leaf blade abaxially pale green, adaxially dark green or brown, lanceolate to oblong-lanceolate, 8-12 × 2.5-3.5 cm, membranous or thinly papery, both surfaces glabrous except barbellate at vein axils, midvein raised abaxially, slightly impressed adaxially, secondary veins in 5-8 pairs, arcuate curved, reticulate veins prominent, base cuneate or rarely obtuse, margin ± crenulate-serrate or repand, rarely entire, apex acuminate or subcaudate. Racemes axillary, to 3 cm, many flowered; rachis glabrous or sometimes puberulous; bracts slightly spreading, linear-subulate. Pedicel slender, 2-3 mm, glabrous. Calyx shallowly funnelform; lobes triangular, glabrous. Petals white, narrowly ovate-lanceolate, ca. 2 × 1.5-1 mm, glabrous, apex acuminate. Stamens subequaling or slightly longer than petals; filaments pilose; anthers oblong-globose. Ovary superior, sparsely puberulous. Capsule ca. 4.5 mm, slightly puberulous, many seeded. Fl. and fr. May-Jun. 2n = 22*.
This species is sometimes cultivated.
* Sparse forests; low to medium altitudes. Taiwan.