Plant walls, art and improving our environment

I’ve seen a new approach to use of ornamental plants several occasions recently: walls of plants covering outdoor and indoor sites. At the indoor site, in Heathrow Airport, I was even more happy to see that Patrick Blanc, credited with conceiving the ‘indoor living wall’ in the legend next to the plantings, is described as a ‘botanist’. The walls, whether indoors or outdoors, give a different aspect to what otherwise would be very unremarkable surfaces. The three uses I have photographed are contrasting sites: indoors, on a temporary hoarding covering a construction site, and on an office building. The Heathrow wall run by Jet Airways certainly made an entirely internal room much more pleasant than simply adding a few pot plants in the corner, and the moisture, lighting and sound absorbing characters counteracted some of the air-conditioned feel that such spaces often have. The office building was in Paris, on the Quai Branly, the south bank of the Seine near the Eiffel Tower, while the wall hiding construction was part of the National Gallery in London’s Trafalgar Square (thus making a notable historical contrast with the Napoleonic monuments and buildings from the other side found along the South Bank of Paris!).

Of course, climbing plants have been covering outdoor walls for centuries, although they do seem to be more abundant in pre-1900 pictures of buildings than they are now: people tend to have become suspicious even of ivy (Hedera helix) or Virgina Creeper (Parthenocissus quinquefolia) on their walls, harbouring insects and damp while etching the surface to cling on. I’m happy with climbers, but am not so sure about that I would trust the technology of irrigation and waterproofing to install walls of plants like these either indoors or outdoors in my house! The lighting in the indoor site also looks unlikely to sustain most species, apparently with filament lights rather than high-pressure mercury vapour lights more suitable for plant growth (another specialized and over-priced product that e-bay purchasing has revolutionized).

The resources in making and maintaining these walls must be considerable – preventing deterioration of the structural wall behind, growing them during different seasons, and circulating water and nutrients.

The choice of mostly leafy species, all requiring considerable water, suggests maintenance will be high, but maybe more work is needed for plants suitable for these locations, just as has been carried out for plants on roofs – for example in Annals of Botany last year by Scott MacIvor and colleagues.

But the living green walls certainly improve the quality of three large public spaces, showing that people really do appreciate the contribution that plants make to the built environment.

J. Scott MacIvor, Melissa A. Ranalli, and Jeremy T. Lundholm
Performance of dryland and wetland plant species on extensive green roofs
Ann Bot (2011) 107(4): 671-679 http://dx.doi.org/10.1093/aob/mcr007