Woolly Pockets are hanging containers from recycled plastic bottles to hold soil, compost and plants.

Defining Terms
Nigel Dunnett and Noel Kingsbury in Planting Green Roofs and Living Walls define living walls as plants rooted in a growing medium on the outward face of the wall rather than behind the wall facade. ?EUR??,,????'?????<

Hydroponics was pioneered by Patrick Blanc, a French researcher, designer and tropical botanist. His system grows the plants without soil, using a balance of water and nutrients. In lieu of soil is a wool felt-like blanket for roots to take hold, a waterproof backing (PVC sheet) and drip irrigation to keep the felt wet. There is normally a pump to recirculate water collected at the base of the wall. If the plant selection is appropriate for the climate, maintenance is minimal, just annual clipping and removal of dead foliage.

Challenges
Not all vegetated walls are easy to grow or maintain. Ms. Philips notes a recent failure for an interior moss wall at the California Academy of Sciences in San Francisco. They could not get the right mix of light and water nutrients, and so the moss wall was nixed before the museum opened. These walls, she says, are more water and resources dependent, use more energy and are more costly than other living wall types.

Another challenge for living walls are vegetation mats, a system used on green roofs that consists of drought-resistant sedums. Walls do not receive direct rainfall or direct sunlight and have to deal with direct wind. ?EUR??,,????'?????<