National Birch Collection - Bethlehem Wood

Location

Bethlehem Wood, located a short walk west of the Main Entrance and Visitor Centre, is comprised almost entirely of birches. There are more than 340 hybrids, cultivars and species, and they represent the National Collection.

What is a National Collection?

Loss of variety within horticulture in the 1970s led to the foundation of the National Council for the Conservation of Plants and Gardens (NCCPG - now called Plant Heritage). The Council set out to conserve the rich garden flora of the British Isles by forming ‘national plant collections’. The idea is that each collection is as complete a representation of a genus or section of a genus as possible, incorporating both species and cultivars. Today, there are some 650 National Plant Collections representing around 350 genera. Wakehurst Place holds four National Collections. 

About birches

There are more than 50 species of birch trees and shrubs growing in the world’s northern temperate and Arctic regions. They are noted for the colours exhibited by their bark, which range from white to apricot through cinnamon to dark cherry red and chocolate. The whiteness of the bark derives from the chemical betulin. Betulinic acid has been found to act against malaria, inflammation and HIV. Extracts from birch can be used to treat snakebites and provide insecticides. Birches are also economically important for their timber, which is used to make furniture, flooring and plywood.

Things to look out for

Wakehurst’s birches are subdivided into Asian, European and American continental zones that demonstrate the genus’s vast geographic range. Specimens range from Britain’s common white-trunked silver birch (Betula pendula) to a sleek red-brown-trunked Betula albo-sinensis from west China. There is also one of North America’s rarest trees, the Virginia round-leafed birch (Betula uber). This species was once thought to be extinct; cultivating the tree at Wakehurst is helping to contribute to its survival. In early spring, the ground beneath the trees is coloured yellow with primroses; this gives way to blue as bluebells come into bloom during May.

Kids’ mission

The colour of a birch tree’s bark can be influenced by environmental conditions, especially the type of soil. There are two Asian birches (Betula ermanii) in Bethlehem Wood that demonstrate this; although they are the same species and are planted close together they look very different. Can you find them and describe the bark of each? What are the similarities and differences between them?