Black alder is an upright tree native to Europe and Asia. It can reach a height of 80 feet in the wild. It actually prefers wet conditions and is often found on riverbanks in its native habitat. Related to birches, it produces catkins in the spring. The female flowers become tiny decorative cones. The leaves are glossy dark green and round, with a distinctive notch at the tip. While this tree is attractive, it does tend to reseed and is considered invasive. This species is slowly being replaced with native alder trees.