Alnus x spaethii is a deciduous hybrid tree that is a cross between Alnus glutinosa (commonly known as black alder) and Alnus incana (gray alder). It is commonly referred to as the speckled alder.
The tree typically grows to a height of 10-15 meters (30-50 feet) and has a spread of 6-9 meters (20-30 feet). Its bark is gray-brown and smooth, with white lenticels. The leaves are dark green and ovate, with serrated edges and a pointed tip. The flowers are inconspicuous, appearing in early spring before the leaves emerge.
One of the distinguishing features of Alnus x spaethii is its attractive speckled bark, which is a combination of gray and white. This makes it a popular ornamental tree for landscaping.
The tree is relatively hardy and can tolerate a variety of soil types, including wet soils. It prefers full sun to partial shade and can be propagated through seed or cuttings.