A. negundo is an often multi-stemmed tree reaching a height of no more than 20 m and a stem diameter of up to 1 m (Rosario, 1988). In more open vegetation the canopy usually exhibits a broad and open crown and may even become shrubby, whereas in the face of competition in a forest stand the trunk tends to be single-stemmed and straighter. Shoots are green and turn violet in the second year. The bark is grey-brown becoming dark grey and is shallowly cracked. Buds are opposite, small, 2-5 mm, two-scaled and silky white. The leaves are 15-35 cm long, pinnate with 3-5 (or 7) leaflets and light green but paler below. The leaflets are lobed and serrated. Leaflet shape is variable, for instance in var. interior the first pair of leaflets is 3-lobed. Male flowers are born in corymbs with pendent stamens whilst female flowers are in small pendent racemes. Both types of flowers are small and pale yellowish-green in colour. There is much variation in the morphology of pistillate flowers with the presence of stamens on a proportion of the flowers (Hall, 1951). The fruit consists of two fused winged samaras to 4 cm long, diverging at an angle of less than 60 degrees. The samaras separate when shed and contain a single wrinkled seed.
Related invasive species
- Acer negundo
Related Farm Practice
- Light
A. negundo is a small and variable tree of little economic value native to much of North America. It has been widely planted mainly for amenity purposes in non-native parts of North America, Europe and Asia where it is now regenerating freely and spreading, invading riparian zones and urban areas. In the temperate parts of the southern hemisphere the spread of A. negundo is more limited. Although this pioneer species is invasive throughout much of its introduced range, actual impacts are not great. This species has no important negative impacts on human activities. In natural habitats the species becomes an important component of the vegetation in riparian systems and increases siltation.
Some abandoned pastures, for instance in Poland, are readily colonized by A. negundo (Falinski, 1998). It is an occasional invader of cropland and forested areas including plantations.