Beech Gardens and the associated High Walk areas at The Barbican Estate, London, are ten years old in 2025. They have proved to be a fascinating living experiment in sustainable and climate-adapted planting. I’ve long felt that if ecological ideas are fully and truly applied in garden and landscape design, then it is utterly transformational. It not only profoundly changes the way places look, but also who uses and enjoys them, how they feel and, of course, how they are looked after and gardened.
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These changes are exciting, and at the same time challenging, and this has certainly been true here. The Barbican itself is a well-known masterpiece of Brutalist architecture, largely built in the 1970s. It is both Europe’s largest arts centre all under one roof, and a residential estate, with 4,000 residents. Originally, the landscape epitomised Modernist minimalism, with empty plazas and trees in planter boxes set out in grid patterns. This proved to be so bleak, however, that a more human-scale and organic scheme of gardens and planting was designed in the 1980s by landscape architect Janet Jack.
All of these garden areas, which are fully public, are roof gardens, in that they sit over the top of underlying rooms, galleries, car parks or roads. Over the past 15 years, it has become apparent that the waterproofing of the building beneath these gardens has deteriorated, leading to water leaks into spaces below, resulting in the need to renew the weather-sealing using modern technologies.
To achieve this, there was no alternative but to remove all the existing landscape, get back to the original roof-deck, and then build up again with replacement gardens. Beech Gardens represented the first phase in that ongoing re-waterproofing project. Previously, the roof gardens comprised lawns, bedding plants, groundcovers, trees and shrubs, which required continual irrigation and a high maintenance regime, in what might be termed a municipal horticulture style.
I was invited to develop the new replacement gardens, and this presented the opportunity to take a radically different approach. In particular, the City of London Corporation (the local authority responsible for the management of the gardens) agreed not to install an automatic irrigation system for the new gardens, and instead to work with a low-water-use, dynamic-planting approach.
Conceptually, the planting scheme consists of three main designed plant communities that are suited to different microclimates around the site, according to how much sun different areas receive, and the depth of the growing medium that was possible. In very open, sunny, exposed, windy conditions with relatively shallow depths of growing medium (200-300mm), I developed a designed ‘steppe’ grassland, using grasses and perennials that are naturally adapted to dry, stressful conditions.
Where the underlying structural support of the building allowed greater substrate depths, I designed a ‘shrub-steppe’ planting that combined similar mixes of dry-tolerant perennials and grasses to the steppe plantings, but with additional scattered low-density shrubs and multi-stemmed trees. Finally, in more sheltered and shaded areas, dry woodland plantings used widely spaced multi-stem trees to create a light, open canopy, with a scattered understorey of shrubs, and a diverse perennial ground layer, with many white-flowered plants to bring light to the shade.
One of the key outcomes of our extensive public consultation (to test the response to the change from conventional horticulture to a radical naturalistic approach) for users was a general dislike of the idea of a landscape that became dead-looking in the winter. There was a feeling that The Barbican was bleak enough. So, I changed the scheme quite considerably to include a high proportion of winter-green plants, and this has influenced how I work ever since.
After ten years, the gardens have developed into a combination of a remarkably stable framework or matrix of robust plants and ‘pop-up’ plants that dance around within that framework. The main steppe areas consist of a matrix of grasses, Sesleria nitida and Helictotrichon sempervirens, both of which have evergreen, steely green-grey leaves. In spring, the white flowers of the Sesleria shimmer above the leaves below, and the thimbly seedheads stay on the plants for a full year.
Within the matrix, a succession of flowers pop up, from early Primula veris and Tulipa praestans ‘Fusilier’ in March through to Aster amellus ‘King George’ and Kalimeris incisa ‘Blue Star’ in November. Scattered low domes of evergreen Euphorbia characias ‘Humpty Dumpty’ are a permanent presence throughout. Euphorbia characias subsp. wulfenii has become another signature plant. It starts sending up flower spikes in December and January and is in flower from late winter to May. The spikes are left in place into summer, turning orange-brown, and are removed to the base in June and July.
The multi-layered plantings with trees, shrubs, grasses, perennials and bulbs have become a prototype of the type of naturalistic planting I now use widely, and I think mark an important move away from the grass-and-perennials-only dominated plantings that have been at the forefront of the naturalistic planting movement for decades.
The dynamic plants are another key element. I always use a proportion of short-lived ‘filler’ plants in my planting – these fill space before the longer-term plants reach their final sizes. Many of these short-lived perennials, annuals and biennials are prolific self-seeders and maintain a presence into the future.
At The Barbican, the wonderful Erodium manescavii remains prominent, along with Silene coronaria ‘Alba’ and the steppe grass Melica ciliata, for example. The growing medium contributes enormously to the ongoing diversity of the Beech Gardens plantings – it is a low-fertility, free-draining, green-roof substrate, with a high aggregate content, based on crushed brick and tiles. No additional fertiliser has been added over ten years.
Of course, dynamic plantings such as this need dynamic gardeners. We have been lucky that there has been a succession of gardeners, including Judy Ubych and Ruby Sweet, who have just ‘got it’ and taken Beech Gardens to their heart, and made their own great contribution to their success.
We are now entering an exciting second phase of The Barbican re-waterproofing project (in collaboration with design and engineering practice Atkins). The new area is twice as large as Beech Gardens, and will provide a continuous 350m-long pedestrian link through the plantings, from The Barbican underground station through to the external entrance to the Barbican Conservatory.
In the first phase, we weren’t able to alter the original size and shape of the planted areas because of their heritage listing. In Phase 2, strong biodiversity and climate policies by the City of London Corporation have enabled us to increase the total area of planting by 75 per cent. The new planting evolves the Phase 1 ideas and maintains the same character, but with an increased proportion of shrubs in places. We were given the challenge by Historic England to develop a contemporary interpretation of a 1980s planting style, again because of the heritage listing of The Barbican landscape, so we have worked with an exciting combination of a diverse ground-layer tapestry of resilient plants, through which will rise woody plants with strong architectural form and bold foliage.
USEFUL INFORMATION Find out more about Beech Gardens at thecityofldn.com