Woolbeding Glasshouse (Silk Route Garden), Woolbeding Gardens

The Woolbeding estate, in the valley of the Rother, passed to the National Trust in 1956, given up by the Lascelles family to offset death duties. After eighteen months empty, the house and gardens were leased to Simon Sainsbury and Stewart Grimshaw; the architectural press dates the lease to 1972. Lanning Roper, then Julian and Isabel Bannerman, shaped the gardens, which opened to visitors on 7 April 2011.

The glasshouse is the last project funded by the Monument Trust, a foundation set up in 1965 by Sainsbury and Grimshaw and closed in 2018. The Woolbeding Charity, formed in 2017 to complete that foundation's remaining commitments, owns and operates it; the National Trust supported it and manages visits. The Charity reports a final legacy grant of almost £11 million for the design, construction, planting and maintenance of the glasshouse and garden, while Architecture Today puts the project itself at £5.8 million. Heatherwick Studio says it was conceived with the Charity and the Trust in the spirit of Victorian ornamental terrariums; the Trust speaks of six years of design, construction, testing and planting.

On the opening date, Heatherwick Studio unveiled the glasshouse on 27 June 2022 and lists Thursday and Friday openings from 28 April to 30 September, while the Trust's history page dates it to 2021.

Heatherwick Studio describes ten steel "sepals" with a glass and aluminium façade. Architecture Today calls it a pyramidal glasshouse with ten aluminium-framed facets that splay open like sepals in a pinwheel for ventilation. Open, the structure forms a crown and frees up 141 m². A hydraulic mechanism deploys it in four minutes on warm days, giving the plants sun and air; in colder weather it stays closed and shelters the subtropical species.

The engineers and firms named by ArchDaily and Architecture Today are Eckersley O'Callaghan (structure and façade), Atelier Ten (environmental design and building services), Bellapart (detailed design and construction of the glasshouse), Eadon Consulting (moving structure), RW Armstrong (main contractor) and Kirkwood McLean Architects (contractor's architect); MRG Studio designed the landscape.

The Trust presents the Silk Route Garden, crossed by a path in twelve stages, as a set of plants, shrubs and trees representing the main regions of that route. Heatherwick Studio counts more than 300 species and twelve distinct regions: Mediterranean evergreens, with a rare mullein (Verbascum) grown from seed brought by a friend of the garden, through to Gallica roses, introduced to Europe by traders from Persia. Rosemary, lavender and fennel recall the plants that reached Britain along the route. The Charity states that Great Dixter led the planting design and propagation.

The glasshouse shelters subtropical species: a rare Aralia vietnamensis shades tender ferns, alongside umbrella trees, magnolias and bananas. A Charity representative sees in it the flora of subtropical south-west China, at the end of a path retracing the Silk Route.

The glasshouse stands at the edge of Woolbeding Gardens, at the end of the Silk Route Garden path, in a 26-acre garden where the National Trust also lists the Tulip Folly, a ruined abbey, a Gothic summerhouse, a river-god grotto and the William Pye fountain. Entry to the glasshouse is included in the garden ticket, which every visitor must book in advance; there is no parking on site, and a free shuttle runs from the Grange Centre car park in Midhurst.

The sepals open in warm weather and stay shut in cold, so the open crown is best seen on a fine day. The garden is closed for the winter; the National Trust announces reopening on Thursday 15 April 2027, with ticket-release announcements in April.