The Hanging Gardens of Carlton House Terrace

April 08, 2021

Project Details

Architect: Eric Parry Architects

Planter Design: Chris Brammall, CB Arts

Planting Design and Installation: Alaster Anderson

Planting completed: January 2018

The PROJECT

When Eric Parry Architects asked us to collaborate on a project at Carlton House Terrace, we saw immediately that it would require a great deal of creative ingenuity – as well as planting expertise. We leaped at the challenge and are delighted with the outcome, which we like to think is a great example of Alaster Anderson flair and problem-solving innovation.

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THE BACK STORY

Eric Parry Architects knew of us from our work in Eaton Place, installing four 6-metre-high phyllostachys (bamboos) to create screening for a courtyard. These were towering specimens, showcased in bespoke planters and providing instant impact. We sourced the bamboos from a specialist nursery in Italy, supplied and installed them.

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At Carlton House Terrace the architects wanted feature planting to rise up a soaring stairwell to a lofty glass roof. Their plan was to plant bamboo, or a tree, and they called upon our expertise again.

THE FIRST CHALLENGE

We identified a number of challenges, however. Crucially, the site had relatively little light, particularly at basement level. We were also concerned about the air temperature and humidity. In a nutshell, there was every reason to expect that in these conditions either bamboo or a tree would fail.

OUR EXPERTISE

With our trademark creativity, Alaster suggested a hanging planter as an alternative. The architects loved the idea and mocked up a design for seven planters suspended from the ceiling, one below the other with foliage cascading from each. Chris Brammall of CB Arts was commissioned to design and fabricate the planters and the hanging mechanism. He came up with a breath-taking cantilevered system – a hanging feature plunging 26m from top to bottom through the centre of the building. As part of the design team, we were asked to evaluate the feasibility of this solution and agreed it would work.

MORE CHALLENGES

Now came the design and installation of the planting scheme. There were a couple of issues:

How it was to be irrigated
What to do with the water when it reached the last planter

Water would be fed down through the planters, with the excess dripping out of the bottom into a feature bowl on the floor … but we needed that bowl to be crystal clear, not full of muddy brown liquid!

Further challenges were weight – the cantilevered system could not support a heavy load so the planting material had to be light-weight –
and the fact that the scheme had to look instantly impressive on installation.

OUR APPROACH

Alaster therefore set about designing a planting medium that would retain moisture so there would be as little excess water as possible, and that was clean so the run-off was clear. To perfect this we built a bespoke greenhouse to test a no-soil planting medium, experimenting and monitoring the results until we were satisfied.
We needed to choose plants that could tolerate low light levels and had sculptural qualities that would look great as they dangled from the planters – luscious houseplants would be ideal.
Having made our choice we took delivery of the planters Chris had made and planted them up, still in the greenhouse. We grew on the plants for six months until they were established, ready to be spectacular from day one in situ at Carlton House Terrace.
When it came to installation we worked alongside Chris’s team. Scaffolding was erected, starting from the top of the stairwell and working down. As the team set each planter in place, Alaster installed the planting and irrigation.