NATIVE RANGE: North America

PATHWAYS: horticulture, silviculture

POSSIBLE TO DETECT: year-round

FLOWERING SEASON: April – May

DESCRIPTION: Dioecious, deciduous, medium sized tree. Usually growing upright; in the shadow of other trees sometimes bending or trailing. Bark thin with shallow furrows, on young shoots green, later turning to grey or light brown. Leaves opposite, pinnately compound with 3 to 5 leaflets (sometimes 7). Leaflets are widely lanceolate to ovate with a short petiole. Terminal leaflet often three lobed. Leaflets light green above, and paler below. Flowers yellow-green, with long stalks, in hanging clusters. Fruits paired V-shaped samaras, in hanging clusters.

HABITAT: Riparian forests, ruderal sites and urban habitats.

STATUS: Widely established throughout Europe. In Slovenian it is common in lowland parts, especially along watercourses and in urban habitats, where it is spreading quickly. 

SIMILAR SPECIES: Vine-leaved maple (Acer cissifolium) and Nikko maple (Acer maximowiczianum) have similar compound leaves with three leaflets. Vine-leaved maple always has only three leaflets which have serrated margins and red stalks. Nikko maple has broad leaflets which are shallowly serrated with obtuse teeth. The undersides of its leaves are hairy and greyish.

SOURCE: Field Guide to Invasive Alien Species in European Forests