Westonbirt, the National Arboretum, holds one of the world's largest collections of trees and shrubs across 600 acres of Cotswold countryside near Tetbury. The collection was begun in 1829 by Robert Holford, a Victorian landowner of unlimited means, and expanded by his son and subsequent owners before passing to the Forestry Commission in 1956. It now contains around 15,000 labelled specimens from around the world, with particular strengths in Japanese maples, North American oaks, and southern beeches.
The arboretum is at its most spectacular in autumn, typically October into November, when the maple glades in the Old Arboretum turn deep red and orange. The display is one of the best in Britain and the arboretum becomes extremely popular on autumn weekends. Spring, when the cherry blossom and magnolias are in flower, is the other peak season.
The site is divided into the formal Old Arboretum, with its structured drives and specimen trees, and the wilder Silk Wood to the south, which is managed more naturalistically and contains ancient woodland alongside the planted collection. A treetop walkway offers elevated views through the canopy.
Westonbirt is well managed and well signed; a visit takes two to four hours depending on pace.