Citrus japonica 65-120cm | Kumquat | Fortunella - Kumquat | Fortunella The Citrus japonica, commonly known as Kumquat, is a charming addition to any garden or indoor plant collection. People value Citrus japonica not only for its attractive appearance but also for its unique, edible fruits that add a tangy zest to culinary creations.Citrus japonica has its origins in Asia and belongs to the genus Fortunella.