“Technically it’s a cinch,” Patrick Blanc says, and with a wave of the hand ticks off the ingredients needed to build a plant wall: ten-millimeter-thick waterproof PVC slabs covered with a polyamid felt, into which holes are cut for the plants; a small hose, punctured every ten centimeters by a two-millimeter hole, to run the length of the top of the wall; a timing device to ensure regular, light watering—like a trickle slowly wending its way down a mossy rock.
The ensemble is then attached to a metal structure that stands out from a supporting wall, trapping a cushion of air, which acts as insulation. Outdoor walls take small plants and seedlings straight from the nursery, while fully mature plants are used indoors. A plant wall by Blanc is made to last at least 30 years with only minimal maintenance.
Beyond the bare guts and skeleton, however, the wall requires an expert eye to choose the flora and lay it out in harmony with light, climate, and the built environment. At the Dimanche house, Blanc took into account that the wall would be contemplated from different perspectives—from a mezzanine at eye’s length with the ceiling, the staircase below, the street beyond, and the room itself. The family wanted a forest canopy feel but without any bushy branches that would diminish the room, and they wanted a variety of blooms all year long but without floral overload. Blanc, drawing on an intimate knowledge of sequencing of plants in natural environments, drew up a “tapestry” that mapped out the 150 species, mostly low-light tropical and subtropical varieties available in commercial nurseries. Gardeners brought the plan to life by weaving the plants into the felt and allowing them to take a shallow hold. Once the PVC was mounted, it was merely a question of time—a few months, in this case—for the plants to expand across the wall, creating a patchwork of texture and tone in constant evolution. —M.H.