Description from Flora of China
Viola tricolor var. hortensis Candolle.
Herbs annual, biennial, or perennial, 10-40 cm tall. Stems erect or slightly oblique, slightly robust, angled, simple or numerously branched. Basal leaf blade narrowly ovate or lanceolate, long petiolate; stipules large, leaflike, deeply pinnatifid, 1-4 cm; petioles of upper leaves longer, those of lower leaves shorter; cauline leaf blade ovate, oblong-orbicular, or oblong-lanceolate, base rounded, margin remotely crenate, apex rounded or obtuse. Flowers solitary in leaf axils, usually 3-colored (purple, white, and yellow), large, 3.5-6 cm in diam., with 3-10 flowers per stem; pedicels slightly robust, 2-bracteolate at upper part; bracteoles opposite, ovate-triangular, very small. Sepals green, oblong-lanceolate, 1.2-2.2 cm × 3-5 mm, margin narrowly membranous, apex acute, basal auricles developed, 3-6 mm, margin irregular. Corolla flat; upper petals deep purple-violet, lateral petals and anterior one 3-colored, purple-striate, lateral ones inside densely barbate at base; spur of anterior petal smaller, 5-8 mm. Ovary glabrous; styles short, base conspicuously geniculate; stigmas enlarged, globose, with a large stigma hole in front. Capsule ellipsoid, 8-12 mm, glabrous. Fl. Apr-Jul, fr. May-Aug. 2n = 26.
Widely cultivated in China [native to Europe].