Tree with catkins is a term used to describe two types of trees, ALDER and HAZEL. ALDER is a deciduous tree that is native to Europe, North Africa, and parts of Asia. It produces small, cone-like catkins that are reddish-brown in color. HAZEL is a deciduous shrub or small tree that is native to Europe and parts of Asia. It produces long, yellow-green catkins that are often used in floral arrangements. Both ALDER and HAZEL are popular ornamental trees and are often used in landscaping.