A great design for gardens on high is just as important as weatherproof plants and pots that won’t blow over the rooftops. You can also be braver, because there are fewer constraints than gardening on the ground: no neighbour’s leylandii, no swathes 1 of shade, no awkward dips or slippery slopes. “At ground level, you are inhibited by the buildings. But above that line, your relationship is with the sky — and that gives you a real freedom,” says minimalist designer Christopher Bradley-Hole, who is renowned for his use of limited plant groups contained within spare, geometric lines.
He makes the point admirably in a vibrant rooftop garden that owes its colour to paint rather than plants, its layout to the strategic placing of custom-made containers and its liveliness to exuberant, easy-care grasses that swish and sway in the wind. “The Canadian couple who own the apartment beneath and had been gardening on the roof had a few plants in pots, but no unified design,” he explains. “And because the site is very exposed, some of the plants suffered. Out of the 23ft by 43ft space, they wanted a defined area for dining and separate ones for plants — ones that would thrive in the exposed conditions.” Situated on top of a converted industrial building in Islington, there was no need to reinforce the roof or have the site surveyed first — things that anybody considering a roof garden should do. “The siting of your containers should relate to the
Swaying in the wind: Christopher Bradley-Hole says that grasses in a rooftop garden add movement and look beautiful
perimeter of the space and the structure beneath,” says Bradley-Hole. “Try to find out where the beams are, which can take the weight, and avoid loading mid-span — even industrial buildings can’t take unlimited weights. Don’t forget that wet soil is incredibly heavy. I always mix Vermiculite in with soil-based compost to make it lighter as well as more free-draining.”
Bradley-Hole made a long, narrow walkway from the entry point and turned it at right angles into a large, square dining area. He used two contrasting landscape materials to mark the different territories. “The terracing is made of Western red cedar, which floats a little above a gravel layer, where the planting areas are. The idea is to have the textural contrast of smooth wood with the less refined gravel.”
There is a practical purpose to the gravel, too. It makes an ideal drainage medium for the pots to sit on, so that they do not become waterlogged.
At ground level, says Bradley-Hole, you might paint your garden walls in gentle, muted colours. But in a high-top space such as this, where the light is stronger, bright colours look wonderful. “When I first went up to the garden, there was such tremendous light that I felt the space was more California than London. Bright red and sharp yellow, next to one another, pick up the spirit and freedom of the space.” Some of the remaining walls were painted mid-grey, to serve as a backdrop.
Containers, provided they are substantial, do a fine job of defining different areas. Bradley-Hole commissioned roomy galvanised planters from a company that supplies corn bins for agricultural farming. “The rectangular containers define the terrace, and on the outskirts, large, separate cylinders make you read the plants individually,” he says.
Bradley-Hole’s favourite plants for using on a roof are tactile, constantly moving ornamental grasses. “There is a strong connection with the sky and the light, and grasses are fantastic for picking up on the elements,” he says. He stresses that they are comparatively easy plants and they suit containers well, provided you feed and water them regularly, and cut them right back in February so they can regrow in spring.
“The clients also wanted purple-flowered Iris pallida — which Hole also planted the Londoner’s favourite tree, the olive, which, provided it does not become waterlogged, is a great weatherproof choice for a rooftop plant.
“It’s very important to get the proportions right,” he says. “Spend time working it out, defining different areas and playing around with them on paper.”
z. Christopher Bradley-Hole: 020 7357 7666;
www.christopherbradley-hole.co.uk.
;:,: Galvanised containers to order from McVeigh Parker
(www.mcveighparker.co.uk).
: Grasses used on roof terrace: Stipa tenuissima;
Calamagrostis acutiflora Karl Foerster; Miscanthus Feme
Osten; Cortaderia richardii; Miscanthus Gracillimus
M$MM
Pictures by GAP Photos