General: The black alder is found in almost all of Europe as far as West Asia and North Africa. It is a definite pioneer wood and unrivaled on damp and waterlogged soils. Thanks to cork pores at the base of the trunk, it is able to supply its roots with air even in the event of brief flooding. In addition, it forms many sinker roots and has the deepest roots of all native tree species. Incidentally, there are small, bulbous growths on the roots. This is a symbiosis between a bacterium and the alder that supplies it with nitrogen. For this reason, the alder also sheds its leaves green in autumn, as it is always adequately supplied with nutrients and does not depend on storage from the leaves.
Care as a bonsai: The black alder needs plenty of water in summer. You may have to water twice a day or even put them in a bowl of water. The shoot and root growth is profuse and the plant should be cut and repotted regularly. However, the last cut must not be made too late in the year, otherwise there is a risk that the wound will no longer be closed and the entire shoot will dry back to the base of the trunk! We recommend cutting by the beginning of August. If it sprouts again, the shoots should only be cut back in late winter or spring.
