Wilkinson Eyre / RHS Hilltop Wisley

The new facility at the Royal Horticultural Society’s Garden skilfully creates links between indoors and outdoors

Words by Sophie Tolhurst

Project Info

Royal Horticultural Society
Main contractor
Structural engineer
Michael Barclay Partnership
Garden designers
Ann-Marie Powell
Matt Keithley
Landscape masterplan
Bradley-Hole Schoenaich

RHS HILLTOP – ‘the home of gardening science’ – has been completed by WilkinsonEyre at the Royal Horticultural Society’s (RHS) Garden Wisley in Surrey. It is part of a five-year transformation of the 97ha site, which has benefited from £4m of National Lottery Heritage Funding. The new centre not only provides specialist facilities for ongoing horticultural research, but also allows Wisley to showcase the RHS’s previously unseen work in this area to its visitors.

The Garden Wisley site covers 97ha in total
The Garden Wisley site covers 97ha in total

Wisley is the RHS’s flagship garden as well as it’s oldest, first given to the society in 1903. It is also its most horticulturally diverse; the garden from which it originated, the Oakwood Experimental Garden, was created by George Fergusson Wilson with an ambition to make ‘difficult plants grow successfully’. These were to include lilies, gentians, Japanese irises, primulas and water plants over the years.

Today, RHS Garden Wisley is one of the UK’s most visited gardens – attracting more than a million visitors per year – but many would have been unaware of the extent of its scientific activities. The new facility hopes to share this side of Wisley’s operations with those who visit the gardens, allowing the many school groups and other visitors to watch live experiments and speak directly with scientists about their work.

The two wings of the centre are joined by an exhibition space in the middle
The two wings of the centre are joined by an exhibition space in the middle

The 4,750m2 facility contains state-of-the-art scientific laboratories, public exhibition space, teaching studios, offices, a cafe and an events hall. It also houses Wisley’s nationally significant Herbarium, science and library collections – housing vast numbers of dried plants, insects, books and art that date back over five centuries – providing the ‘most complete record’ of the UK’s horticultural heritage.

The centre is located on a hilltop site within the gardens, positioned to respect existing mature trees and the natural history of the site. It is surrounded by four acres of ‘living laboratories’ or science gardens, designed by Matt Keightley and Ann-Marie Powell as part of the gardens’ new landscaping, masterplanned by Christopher Bradley-Hole.

the materials palette seeks to create links between inside and outside
the materials palette seeks to create links between inside and outside

The form of the two-storey centre – a ‘Y-shape’ of two wings – opens up around its entrance to welcome visitors and extend out into the surrounding gardens. It has been designed to maximise connection between the building and surrounding science gardens, allowing activities to be carried across indoor and outdoor spaces. The east wing contains the laboratories and library collections, opening out to the wildlife garden; the west wing contains the more public-facing areas and education spaces and faces the world kitchen garden. The two wings are joined by a double-height glazed exhibition space in the middle, which has a pitched roof clad in standing seam metal. The main entrance is located here, between the opening of the wings and below a cantilevered canopy, welcoming visitors via the health and wellbeing garden.

There are extensive visual connections between inside and out and between internal spaces too, such as an internal window between the atrium and the herbarium, allowing visitors to see work of the scientists inside.

the use of natural materials forms a contrast with the building's steel frame
the use of natural materials forms a contrast with the building's steel frame

The materials palette also forges links between itself and its surroundings, with warm wooden cladding – of sustainably sourced and naturally weathering sweet chestnut timber – across both wings. Natural materials continue indoors too, with slatted wood across vertical surfaces and a living wall within the atrium itself. These elements form a contrast with the exposed concrete and angular structural steel frame of the building.

Andrew Jasper, RHS programme director – Wisley, describes RHS Hilltop as a ‘significant legacy project for the RHS and UK horticultural science‘. The significance of the collections held by Wisley – now including four internationally important RHS National Plant Collections: living, herbarium, entomology and pathology – required environmentally controlled spaces to be created within the building.

WilkinsonEyre was able to use its experience in creating giant cooled conservatories for Gardens by the Bay in Singapore to provide the optimum environments needed for Wisley’s collections of more than 86,000 herbarium specimens, 24,000 insect specimens, 28,000 books, periodicals and other literature over 500 years of gardening history.

Geoff Turner, associate director at WilkinsonEyre, commented on the practice’s desire to provide ‘optimum facilities for the vital work taking place’ and added that they hope the completed centre will ‘inspire even greater public engagement with the world of horticultural science and its importance for a greener future’.

Opening up in the same year that the UK is due to host the UN climate change conference, COP26, visitors will be able to learn more about all the research at the centre aimed at addressing climate change – such as working with plants to soak up pollution, ease localised flooding, capture carbon and cool cities. But the centre also looks at how gardening can boost wellbeing and allow wildlife to flourish, with ideas for homes, schools and communities – to hopefully continue to buoy the interest of those who first took to gardening during the pandemic for many years to come.


JP Dunn Construction
Hillcrest Structural
NA Curtain Walling Vincent Timber (sweet chestnut timber)
Strata Tiles (precast concrete)
Shueco (glazing)
Kovara Projects VeioZinc (metal standing seam roof)
MEP services
Interserve Engineering Services
Drylining and ceilings
Macai SAS (metal ceilings)
Forster Ecospace
Laboratory furniture
NHE Texaa (acoustic fabric panels)
BCL (acoustic timber cladding)
Structural Stairways
Glass partitions
Planet Partitions
Floortec Solnhofen (Jura Beige stone floor)

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