NATIVE RANGE: Asia (China, Korea, Japan)

PATHWAYS: horticulture

POSSIBLE TO DETECT: year-round

FLOWERING SEASON: May – July

DESCRIPTION: Small deciduous tree with dense crown and thick, upwardly curved branches. Bark with flat ridge tops. Leaves pinnately compound, with 7 to 15 oval leaflets which have many irregular serrations and acute apex. Young leaflets in spring reddish, in autumn yellow to orange. Flowers small, yellow, borne in branched panicles up to 40 cm long. Fruits triangular capsules, which have three pronounced veins over the middle of each side. In each of the seed compartments there is one globular, black seed. Fruits are initially green, when ripe brown and persist throughout winter.

HABITAT: In its native range growing especially on rocky cliffs with open forest. In Europe also found in riparian forests, urban habitats and ruderal sites.

STATUS: Found locally; most records are from France and the United Kingdom. In Slovenia few recent findings of saplings in the vicinity of planted trees. 

SIMILAR SPECIES: Common bladdernut (Staphylea pinnata) and bladder senna (Colutea arborescens) have similar fruits. However, leaves are smaller and compound leaflets with entire margins. Kentucky coffeetree (Gymnocladus dioicus) has similarly divided leaves, but leaflets have an entire margin. The fruit is a long pod.

SOURCE: Field Guide to Invasive Alien Species in European Forests