Guava / Psidium GuajavaGuava fruit plants belong to the Psidium genus, and the most common variety is known scientifically as Psidium guajava. Guava is a tropical fruit that is widely cultivated in many tropical and subtropical regions around the world. It is appreciated for its sweet and tangy flavor, as well as its rich nutritional content. Guava fruit plants are small to medium sized evergreen trees or shrubs.