9 Silver Birch Betula utilis var. Jacquemontii 4-5ft. Leaves oval dark green and drooping, turning yellow in autumn. Male catkins conspicuous in early spring, to 15cm in length. Betula can be deciduous trees or shrubs, usually colouring well in autumn and often with striking white, pink, or peeling brown bark; separate male and female catkins open before or with the leaves in spring.