Preferred common name: Italian alder The leaves of the RHS Italian Alder (Alnus cordata) are deciduous but with a very long season in leaf, from April to December in the Northern Hemisphere they are alternate, cordate (heartshaped), rich glossy green, 5 12 cm long, with a finely serrated margin. The slender cylindrical male catkins are pendulous, yellowish in colour & 5 10 cm long pollination is in early spring, before the leaves emerge. The female catkins are ovoid, when mature in autumn 2 3 cm long & 1.5 2 cm broad, dark green to brown in colour, hard, woody, & superficially similar to some conifer cones. The small winged seeds disperse through the winter, leaving the old woody, blackish `cones` on the tree for up to a year after. Like other alders, the RHS Italian Alder (Alnus cordata) is able to fix nitrogen from the air. It thrives on much drier soils than most other alders, & grows rapidly even under very unfavourable circumstances, which renders it extremely valuable for landscape planting on difficult sites such as mining spoil heaps & heavily compacted urban sites.