Description from Flora of China
Ballota suaveolens Linnaeus, Syst. Nat., ed. 10, 2: 1100. 1759; Bysteropogon suaveolens (Linnaeus) Blume; Mesosphaerum suaveolens (Linnaeus) Kuntze; Schauera suaveolens (Linnaeus) Hasskarl.
Herbs annual, aromatic, robust, branched, erect. Stems 0.6-1.6 m, spreading hispid. Petiole slender, 0.5-6 cm; leaf blade ovate to broadly ovate, 1.4-11 × 1.2-9 cm, adaxially olive green, abaxially pilose, base rounded to shallow cordate, oblique, margin serrulate, apex subacute to obtuse. Cymes (1- or) 2-5-flowered, in racemes or panicles. Calyx ca. 5 × 3 mm, dilated to 12 × 6.5 mm in fruit, villous, yellowish glandular, throat tufted villous, veins very elevated; teeth broadly triangular, long subulate, 1.5-2 mm. Corolla blue, 6-8 mm, puberulent except near base; tube ca. 2 mm wide at throat; upper lip lobes reflexed; middle lobe of lower lip shorter, lateral lobes similar to upper lip. Nutlets dark brown, 2, flattened, ca. 4 × 3 mm, dotted, with 2 basal white scars. Fl. and fr. year round.
Weeds in open waste areas. Fujian, Guangdong, Guangxi, Taiwan [native in tropical America, widespread tropical weed].