This black poplar dominates the plantings in the Autumn Garden.
During the winter months Populus nigra ssp. betulifolia (black poplar) impresses with its leafless, skeletal form and its deeply fissured bark. It is an imposing and distinctive feature of lowland regions of the British Isles and western Europe, and can live for 200 years and reach 30m in height. The leaves are glossy and heart-shaped, and male and female flowers (catkins) are borne on separate trees, though seldom do both sexes occur in one population. When fertilised the female flowers produce cotton-like seed heads which are wind dispersed to ensure distribution of seed. A member of the willow family (Salicaceae) the genus is subject to much taxonomic debate, with estimates of the number of species ranging from 29 to 100, though the confusion may arise as a result of cross-hybridisation. The genus occurs throughout temperate and subtropical Eurasia, North America and north Africa.