Vertical Gardens ~ Living Walls

by Trevor Smith

The concept of a garden is rising to new heights, literally, as we look up rather than down for new gardening opportunities. Referred to by many different names — vertical gardens, living walls, or green walls — this relatively new form of gardening is taking root in many locations across the globe.

The concept was first demonstrated more than 15 years ago at a garden festival in France, by Patrick Blanc, a French landscape designer who had studied plant aerial growth habits in the tropics. Blanc’s hydroponically-grown plant mosaics soon appeared on prominent buildings world-wide.

Less than a decade later, living wall “systems” were being manufactured by many companies and have become readily available in the past few years. The initial interest in vertical gardens was focused on urban gardening, where traditional garden space is limited. But the beauty and versatility of vertical gardens is now drawing interest from gardeners beyond urban centers. In addition to the aesthetics, some of the benefits of vertical gardens include: lowering the temperature of buildings; air filtration; shielding building materials such as brick and concrete from heat extremes; reducing noise; creating wildlife habitat; providing edible gardening opportunities; water management when used in conjunction with storm-water and grey-water systems; and offering a more visually appealing living environment.

Originally, vertical wall systems were designed for hydroponically-grown plants, but the new systems are made up of modular planted panels that use combinations of growing medium. Individual growing cells are angled to ensure planting medium is stable while allowing maximum light exposure for plant material. Many systems provide 4” deep cells, while other systems offer deeper cells to accommodate wider plant material options. Plant options for vertical gardens include everything from grasses and groundcovers to shrubs and strawberries.

When and how plant material is irrigated is a primary concern in vertical wall installations. Systems are typically designed for efficient water use and the growing medium has been formulated to allow good drainage and aeration while retaining enough moisture to minimize irrigation cycle times. But careful attention must be paid to this area of vertical wall design, to avoid over-watering one section of the planting while under-watering another section.

Most vertical wall systems are irrigated with a drip line, but some are hand-watered. It is important to check to ensure that there is enough water going through the system to irrigate all panels and to carefully regulate the irrigation by setting up the daily watering on timers. Most frames have drip pans and catch basins for indoor applications, while outdoor applications are free-draining. Another consideration when designing vertical wall gardens is the full saturation weight of the installation.

I have used both the panel vertical wall systems as well as the “Woolly Pocket” systems. I find that most commercial soil mixes tend to be light and drain very quickly by design, but by adding biochar to the soil mix, you don’t need as much fertilizer. You will find that there is a lot of variation in the bagged soil mixes for these systems.

The modular panels can be interconnected and provide great flexibility of installation, allowing the designer to create an unlimited variety of sizes and shapes. These systems are designed for use in both interior and exterior applications. Panels are constructed of various materials, including new and recycled polypropylene as well as natural materials such as coconut fibers. Some systems are exclusively designed for mounting directly on a vertical surface while others are mounted on a stand-alone frame. Most can be easily removed and re-installed for maintenance.

There are many new residential applications for vertical walls. They can be used in place of potted plants. “Picture walls” are vertical walls used as art such as this example that I designed and installed at a private residence in Mission Hill, MA.

Some culinary enthusiasts are installing vertical gardens in their kitchens for year-round herb gardening. I have also created another innovative indoor design by constructing a wall-mounted panel to be used as a headboard.

Outdoors, vertical wall systems can be used ornamentally when mounted on walls or fences, or, free-standing installations can be planted with perennials or annuals and serve as portable urban or suburban screening on balconies, decks, or patios.

Vertical garden systems are designed to be used year after year, but special consideration will have to be made in colder climates where panels will need to be taken down or will have to be insulated to avoid winter damage. For example, in the Northeast where I practice, a wall of thyme and strawberries will either have to be brought indoors for winter or will need to be wrapped and allowed to go dormant. Plant material will have to be carefully selected in these cold climates, especially for large outdoor installations.

In addition to these ornamental installations, I envision very practical vertical gardening applications as well.

What if we take a vacant urban lot and fill it with free-standing panels, or create A-frames for use as a community garden? It doesn’t matter what the lot was before, with these systems you can control the soil and water. If the lot is sold, you can just brake down the panels and move them to another location.

I will be displaying some of my other vertical gardening designs at GreenFest Boston, Boston City Hall Plaza, August 19 – 21, 2010. GreenFest Boston is the region’s largest multicultural environmental festival.

A living wall is more like container gardening than a perennial bed, when it comes to managing water and nutrients. But it gets planted like a perennial bed and, like a perennial bed, the wall will be different in subsequent seasons. Just like any perennial bed, it is not a ‘set it and forget it’ landscape element. It is going to need to be tended to – things will die and need to be replaced. Success with living walls requires thought and maintenance. You are going to have to find the rhythm in your wall.

Trevor Smith is the owner of Land Escapes, a full service ecological landscaping company in the Boston area that specializes in Garden Design, Eco-Rain Recovery, Water Features, and Living Wall Installations. Trevor is also the Vice President of the Ecological Landscaping Association. You can reach Trevor through his website: http://www.everydaygetaway.com.

FROM: Vertical Gardens ~ Living Walls

AUGUST 15, 2010