Curator Mark Ballard said: "The new facilities are befitting of a National Arboretum. The area layout will give our team more time to spend on planning and development and allow better control of plant health and bio-security. All this will benefit our world-famous tree collection."
For the first time, visitors will be able to see Westonbirt's vital propagation work. Interpretation and guided tours will show how Westonbirt collects, grows and cares for its trees, and how it has done this for over 150 years.
Learning and participation manager Ben Oliver said: "Visitors are always interested in the stories behind our trees. The new propagation area provides a fantastic opportunity for visitors to get a sneak preview of our specimens of the future and discover the ground breaking techniques we use to look after them."
The new propagation unit is located next to the historic Victorian Keeper's Cottage, where in the 1920s to 1940s the arboretum's first curator W.J. Mitchell lived and wrote his diaries about managing the tree collection.
An official opening will take place on 23 August and visitors to Treefest (25-27 August) can join guided tours of the facility. Visitors can find out more at the Great Oak Hall during the event.