NATIVE RANGE: North America

FIRST FINDING IN SLOVENIA: 1964

PATHWAYS: horticulture; planted for honey bees

POSSIBLE TO FIND: year-round

FLOWERING SEASON: May-June

DESCRIPTION: A deciduous shrub with multiple stems. Leaves are alternate, pinnately compound with one terminal leaflet and 5  to 17 pairs of elliptical leaflets. Leaflets have small pores which are visible when the leaflet is viewed against the sun. Slender stipules are present with young leaves but there are no spines. The purple-blue flowers with yellow anthers are borne on slender, 5–15 cm long spikes at the end of twigs. Fruits are spotted pods about 1 cm long, initially bright green, turning brown when dry.

HABITAT: Riparian habitats, forest edges, coastal areas and ruderal sites in lowland.

STATUS: Widespread throughout Europe. 

SIMILAR SPECIES: Black locust (Robinia pseudoacacia), has very similar leaves but has spines at each leaf scar (often absent on older or slow-growing twigs). Leaflets have no pores. Flowers are white, borne in long hanging clusters. Fruits are flattened, hanging pods, up to 10 cm long containing 4 to 8 seeds.

SOURCE: Field Guide to Invasive Alien Species in European Forests