Traditionally,when home gardeners want to add a vertical element to their yards, they build an arbor, plant a tall tree, plant a palm,or they train a vine to grow up a fence or trellis. These are great options, but the more recent trend is to create a “living wall” – where masses of non-vining plants are cultivated on thin substrates and panels that lack soil. Marrying lightweight technology to modern diversity of plant materials has created an explosion of excitement since the 1990s. No more must a building façade or interior wall be merely draped in vines; today, living carpets of plants can actually mystify, soften and delight the eye to amazing heights!

Patrick Blanc Living wall design

This Patrick Blanc design, in USDA hardiness Zone 8, blends perennials like foamflower, coral bells, hardy begonia, sage and variegated sedge with evergreen ferns and butterfly ginger.

Photo Credit: James Burghardt

Vertical succulent frames

This simple 3- by 3-foot frame of chicken wire was stuffed with sphagnum moss then planted with an array of succulents. Infrequent watering dampens the lightweight sphagnum to sustain the vertical plant growth.

Photo Credit: Maureen Gilmer

Rockwool panels

Panels of insulation, called “modern rockwool” have drip irrigation tubing trickling water through its fibers. Here, prior to planting, a few epiphytic staghorn ferns and tree-dwelling anthurium have been tied onto the aluminum grates.

Photo Credit: James Burghardt

Pinning in Tillandsia

Until the air plants (Tillandsia species) flushed out new roots into the roofing fiber, florist pins anchored each plant onto the arches. (It took about 3-7 months for all the different air plant species to secure themselves and render the pins obsolete.

Photo Credit: James Burghardt

Wall planting

Plant by plant, an array of nearly 400 tropical epiphytes and ground-dwelling plants were tied, tucked and wedged into an organic living wall.

Photo Credit: James Burghardt

Misting live wall

With overhead misters creating a cloud forest effect, this same rockwool wall has filled in after two months.

Photo Credit: James Burghardt

Gaps in arch

Only the imagination limits the arrangement of air plants. Here’s an organic “wild clumping” design as plants are added to hide the black roofing fiber that is atop a steel form.

Photo Credit: James Burghardt

Living arch

Three completed arches reflect more contrived designs, including a spiral, polka-dot and block display. As the air plants flower, many of their leaf rosettes blush with red and pink tones to bring added color and contrast.

Photo Credit: James Burghardt

Now, the challenges to constructing a vertical garden in the traditional gardening sense are obvious, foreboding and usually impractical – and the questions are many: How do you get soil in a wall? How do you water these vertical plants (and how often)? What kind of structure is needed to support a heavy mass of wet soil? What about light? Which plants grow outward rather than straight up?

Let’s get some answers...

This amazing upward growing style goes by many names – “living walls,” “garden murals,” “vertical gardens” and “plant canvases.” The pioneer of this technique, French botanist Patrick Blanc, dubs each “le mur vegetal.” Although many plant lovers and designers around the world now create wondrous living walls both indoors and out, Patrick’s vision to re-create the masses of plants that grow on moist cliff walls is what started it all. Using the lightweight fibers and panels used in modern construction with the nutrient-rich drip irrigation synonymous with hydroponics, he managed to conquer the dilemma of figuring out how to grow upwards without monstrous vines and columns of heavy, soggy topsoil. The living wall boils down to having plant roots growing into man-made fibers for support with dripping water from irrigation lines supplying all the plant’s nutritional needs.

Patrick studied and employed the use of epiphytes (plants that grow upon another plant or structure) in his interior designs. He used standards like tropical bromeliads, orchids and ferns for stunning interior wall designs, as well as lithophytes (plants that grow on rocks) like some cacti, succulents, orchids and mosses. What is revolutionary is that he also familiarized himself with soil-dwelling plants, too. Tropicals such as small philodendrons (like Philodendron hederaceum) and rhizomatous begonias readily made the transition to a vertical surface.

Amazingly, many temperate garden perennials, growing on vertical mats outdoors, were used and exposed to the elements, including winter cold. By using hardy evergreen ferns and groundcovers as the primary year-round visual color and texture on building facades, Patrick also dared to use herbaceous plants for their seasonal foliar color. His designs are renowned in Paris, Madrid, London and Melbourne, as well as in Charlotte, NC; Los Angeles; Miami, FL; New York; and Tacoma, WA. Who would have ever thought a wall of coral bells (Heuchera), short grasses and sedges, spurges (Euphorbia), ferns, mondo grass (Ophiopogon) and sages (Salvia) were more handsome than clay brick and mortar?

I had the challenge of creating two vertical interior tropical gardens in 2007. Abandoning any ideas of using vines and soil, I delved into the world of rockwool and roof venting fiber to fabricate some large vertical plant designs. Rockwool in essence is building insulation, although today it’s made out of fiberglass (rather than melted rock) spun into cotton candy-like fiber. Not only can rockwool hold water, it drains, allows air to penetrate and provides insulation (not to mention makes your skin itch). It’s even soundproof. It became a perfect medium for growing plants…and muffling screams of despair.

With rows of drip irrigation hoses layered above aluminum cages packed with moist “rockwool insulation” installed on an expansive 16- by 40-foot wall, an array of nearly 400 tropical epiphytes and ground-dwelling plants were tied, tucked and wedged into an organic design. As long as the roots of plants came in contact with the moist rockwool, they would grow. Anthurium, philodendron and staghorn fern were the epiphytic plants I used. Earth star, fragrant begonia, various ferns and variegated peperomia were also planted and began sending their roots into the moist material within six weeks.

To prevent premature drying, my wall was oriented away from the hot, direct sunlight of a southern exposure, and more drought-tolerant plant species were placed higher on the wall where light, breezes and gravity would make the rockwool dry faster. Conversely, those plants tolerant of dimmer light and higher humidity were placed lower. The only caveat was that rockwool is naturally very alkaline, so each panel was treated in an acid bath before being installed. Now less basic in pH, the planted panels would take considerable time and dripping to become truly neutral to barely acidic – the optimal pH for most plants.

In a brighter, sunnier location, I opted to use only epiphytes to cloak vertical structures with carpets of color and texture. I would have loved to have tried an epiphytic cactus or succulent (Rhipsalis or Crassula), but my lack of time and need for large numbers of plants led me to a personal bromeliad favorite, the air plant (Tillandsia). Since air plant roots only clasp for support, I used a plastic fiber mat that could initially hold each plant with a florist pin. Some 13,500 air plants later, four immense arches created one of the largest public displays of bromeliads in North America.

The sweeps of air plants needed a warm shower of water a couple times a week from a garden hose, a monthly fertilization, good air circulation and bright light. Even though a bromeliad slowly dies after it finally flowers, the young pup plants at the mother plants’ bases would perpetuate the display. The seasonal flushes of the air plants’ flowers added extra dimension to the vertical, fiber-clad arches.

The fun news is that the basic principles of a vertical mural can be drastically scaled down for application in the average home garden. The easiest method is to still use soil for planting vegetation. Fortunately, today’s modern kits are engineered for size, weight and simplicity. For those savvy in drip irrigation design or hydroponic growing, more “cutting edge” and lightweight vertical gardens can be crafted using insulation panels, carpet padding or other construction material from the hardware store.

Already popular are succulent bowls and topiary forms, and these translate quite readily to a picture frame-like form made of chicken wire and sphagnum moss stapled to a piece of plywood before planting. Just remember to use the right succulents: In frost-free regions, use Crassula, Echeveria and Senecio; and in freezing-winter regions, gravitate toward various stonecrops (Sedum) and hens-and-chicks (Sempervivum). Even some of the dainty rock alpine wildflowers could translate beautifully onto a vertical surface if given the right growing temperatures and conditions.

In tropical regions, smaller portrait-like frames of bromeliads can be pinned onto black roof-venting fiber mats, available at your local building supplier. Whether using the sun-tolerant airplant or Aechmea, or the shade-loving Vriesea or Guzmania, the bromeliad composition can also include orchids like Cattleya, miniature Dendrobium or Phalaenopsis (corresponding with the appropriate light exposure). Just remember to drench the plants on a regular basis – for this reason, your planting is best located outdoors. Overall, any epiphytic plant will translate more easily to a vertical application in a small home garden orgreenhouse.

Modular vertical walls, made of plastic or rot-resistant woods, are becoming increasingly available around the world. Vertical panels that sturdily hold small amounts of soil are also an option. Whether mounted to an interior foyer wall or on castors that can be rolled around the office, these self-contained vertical gardens have a circulating pump to ensure the plants are automatically watered. Some kits even include the plant materials so the process is streamlined; other kits can be basic structures and allow you to select your own plants at your local garden center. Picking your own plants with a modular kit permits the use of hardy outdoor plants in temperate climates on a patio, or tropical plants with low-light requirements for an interior accent in the living room. The possibilities really are endless – as are the visual delights.