Description from Flora of China
Guajava pyrifera (Linnaeus) Kuntze; Myrtus guajava (Linnaeus) Kuntze; Psidium pomiferum Linnaeus; P. pyriferum Linnaeus.
Trees, to 13 m tall. Bark gray, smooth, peeling in strips. Branchlets angular, pubescent. Petiole ca. 5 mm; leaf blade oblong to elliptic, 6-12 × 3.5-6 cm, leathery, abaxially pubescent, adaxially slightly rough, secondary veins 12-15 on each side of midvein and usually impressed, reticulate veins obvious, base rounded, apex acute to obtuse. Flowers solitary or 2 or 3 in cymes. Hypanthium campanulate, ca. 5 mm, pubescent. Calyx cap nearly rounded, 7-8 mm, irregularly opening. Petals white, 1-1.4 cm. Stamens 6-9 mm. Ovary adnate to hypanthium. Style as long as stamens. Berry globose, ovoid, or pyriform, 3-8 cm, with persistent calyx lobes at apex; flesh white or yellow; placenta reddish, well developed, fleshy. Seeds many. Fl. summer.
Psidium guajava has become naturalized in disturbed habitats in many tropical parts of the world.
Cultivated and sometimes naturalized in Guangdong, Guangxi, Guizhou, Hainan, Sichuan, Taiwan, and Yunnan [native to tropical America].