National Botanic Garden, Salaspils
The natural range for this tree species is North America. In Latvia, the Box elder (Acer negundo) began to spread in the first decades of the 20th century, initially in gardens and greenery, but today they have already spread widely in the wild, penetrating natural habitats. Its spread changes the landscape in Latvia, endangering local natural diversity.
A tree or multiple-stemmed bush of medium size, 12–15 m in height. Branches are broadly spread, with a greyish-brown bark, with ridges. New shoots have a bluish frosty tinge. The leaves are compound, formed of 3-7 (9) oblong pointed leaves. The leaf at the end of the branch is the largest.
It is dioecious – male and female flowers are separated on different trees. The male flowers grow as tufted bouquets, the female – as hanging bunches. Bloom from April to the middle of May before leaves start to grow.
The fruits are paired, winged seeds 3–4 cm long.
Manner of introduction
Introduced as an ornamental plant in the beginning of the 20th century.
Characteristics of growing conditions
The most widespread and largest stands are in river valleys. Often found in moderately moist and fertile soils. Can also grow in fairly dry areas – slopes, open spaces and quarries. Very often found in abandoned cultivated fields and meadows, dumpsites, along railway lines, roadsides, even on the roofs of buildings.
Familiarize yourself with invasive species and submit your observataions to: “Invazīvo sugu pārvaldnieks”.
Source: “Invazīvo sugu pārvaldnieks”, Nature Conservation Agency