There’s only one problem, a major issue when hanging out alfresco in the country that invented the raincoat: London’s persistent drizzle and fog. To ward off the chill and warm up the courtyard, Harrison had a few tricks up his sleeve. “The courtyard is very dark, so we created walls in bronzy golds that reflect the warm light into the space; it not only made it brighter, it gave it a warmth,” Harrison says of the walls, lined with western red cedar that practically glows in the heat of the sun. “It’s not trying to show off from an opulence point of view, it’s quite practical. Usually the United Kingdom is cold and damp.”
The key to getting the look, especially in a modernist setting with sleek, floor-to-ceiling glass windows is texture, texture, and more texture. A wide variety of leafy plants—some short, delicate, and lacey, others tall and as brawny as a plant can be, lend in-demand texture. “This client basically has all these memories of his childhood and his aunt’s garden in India, and he wanted a garden that felt like it has that personal touch, like it wasn’t too [intentionally] ‘designed,’” says Harrison, who won the Judges’ Award from the Society of Garden Designers Awards in both 2019 and 2020. Anchoring the space: a towering two-story Indian bean tree that creates a bit of a natural canopy, shielding visitors from sun and rain in equal measure. “They are multistem trees we raised so you can see through them and walk under them, and it creates a ceiling,” says Harrison of the Catalpa bignonioides, which bloom with orchid-esque white flowers in late spring and have excellent drought tolerance once they’re firmly established. “You get human scale and privacy, so you don’t feel like you’re being watched by the neighborhood.”
Another way Harrison created comfort for the homeowner and their guests alike? By installing multiple outdoor seating areas, complete with cushions and seating made of hard-wearing outdoor Sunbrella fabrics so strong they can take a spill of pinot noir—or a entire summer of sunshine—and still look practically brand new. Reclaimed vintage furniture ensures a storied, collected feel in the newly built space. And through it all, a custom zig-zagging staircase encourages guests to wander both levels with a sense of untrammeled discovery. “The gardens are in two separate spaces, so one of the first things we suggested to the client was a staircase,” recalls Harrison. “It helped create lovely appeal between all the layers, so both floors are connected by the garden, continuing movement between all of them so it flows continuously through the space.”
Of course, in order to make it work aesthetically, the staircase in question had to be as visually streamlined as origami while standing as sturdy as steel. “The staircase was very, very important to make the space work, but it had to be very light,” he says. “[The railing] is made of metal mesh so you could still see the back wall.” Flourishing climbing plants will have free range over the structure, giving the sense that “nature has taken over this place.”
There are plenty of plantings in the garden, but there is an obvious lack of Crayola-bright colors; there are no exultant pink roses and no over-the-top blousy purple peonies to be found. “Particularly in a shady spot, there are not many opportunities to introduce color through plantings, so form and texture become even more important,” says Harrison. “Plants only flower for a few weeks maximum, so we are more interested in the form and texture of the plants and their green form. These types of plants have broad seasonality as well.” To ensure elements of the space would remain as green as Queen Elizabeth II’s Greville Emerald Kokoshnik Tiara, he made sure to plant a combination of evergreens and deciduous plants that would take turns prettifying the space throughout the seasons, including Staghorn sumac (an up to thirty-foot-tall shrub with velvety leaves), Sweet box, European ginger, fig, and Martin’s spurge (a native of France).
It is all designed to look wild, but because this garden is on a rooftop it is all planted above-ground, over and around the silver-gray granite floor tiles and crunchy pea gravel. “Everything has to be planted in planters,” says Harrison. “It looks like it’s planted in the ground, but because these gardens are on roof terraces there is no soil. Just remember: the larger the planter, the happier the plant.” And the happier the plants, the happier the people.