Digging the future of vertical gardens

22 December 2014

More and more businesses today are looking to green walls as a way to add natural beauty while dramatically improving energy efficiency by moderating indoor air temperatures and humidity levels.

A green wall, which is also referred to as a living wall or vertical garden, is a wall that is free standing or part of a building that is partially or completely covered with a vegetation facade. Every inspired landscaper digs their shovel into their soul and plants their own nature into their work. Green walls provide an inspired palette for landscape architects to harness and cultivate the joyful power of nature to best serve their clients.

While living walls are becoming de rigueur as the plantings that every green-conscious business desires to visually showcase its initiatives, shoddy systems with poor long-term performance are rapidly flooding the market.

Designing, building and installing beautiful, yet functional and beneficial green walls takes experience and practice. In a buyer-beware marketplace, it is important to invest in a living wall system that has a proven track record of sustainability and to select an installer who has a well-documented history of successful installations with full-scale maintenance capabilities on both plants and irrigation. 

Living plants require water, nutrients and light to survive. High quality commercial vertical gardens come complete with their own “life support” system that’s comprised of a supporting structure to hold the plants vertically, a growth medium to ensure plant longevity, an irrigation/ fertilization system to deliver the correct amount of water and nutrients and a drainage system to properly dispose of or re-circulate the spent water. Proper selection and design of a system for a particular locale necessitates plumbing and electrical considerations. Understanding the lighting needs required for the selected plants is also crucial for sustainability. 

I believe there may be countless reasons why vertical gardens are an important addition to any commercial property. However, for the purposes of this article, I limit my exuberance to my top reasons to invest in a living wall:

• Green walls roll out the welcome wagon — You can’t help but be awed by the beauty of a living wall. Whether a green wall is showcased in an interior setting such as in a hospital, hotel or commercial lobby or in full glory on the outside façade of a building, they make environments look more attractive and welcoming. Syed Hasan, general manager at Embassy Suites Chicago Downtown/Lakefront unveiled Chicago’s largest indoor green wall in his hotel’s sky lobby in June 2011. He believes that the new green wall rolls out a green welcome wagon to all guests and visitors. “Not only is our green wall beautiful to behold but it actively improves the lifestyle of people in urban environments as the average person spends a majority of their time indoors,” says Hasan. “Our green wall also assists in reducing noise levels as plants absorb sound and improve energy efficiency by moderating indoor temperatures and humidity levels.” 
• Breath of fresh air — Vertical gardens provide a net positive impact to the environment over their lifespan. Foliage plants of indoor vertical gardens significantly improve indoor air quality by moderating temperature and humidity levels and filtering the air to remove harmful volatile organic compounds (VOCs). VOCs are “chemicals” which have significant vapor pressures that can be dangerous to human health and have adverse effects on the environment. The EPA has found concentrations of VOCs in indoor air that is commonly two to five times greater than what is found in outdoor air. Sources of anthropogenic (man-made) VOCs include new furnishings, wall and floor coverings and office equipment like printers. In the span of a year, a 50 sq ft (4.6 sq m) vertical garden can consume as much CO2 as a 14 ft (4.2 m) tall tree with as much as one pound of dust removed from the air per square foot. 
• Sign post value of living wall — Living walls can provide a living barrier that gently guides people where you want them to go. In many buildings there is a need to channel pedestrian traffic toward landmarks including check-in desks, escalators and common passageways. This is particularly important in premises with large, open areas such as those found in airports, hospitals, universities, and other large commercial spaces. Living walls provide natural divides and reference points that make any space come alive with vitality. 
• There are no ugly buildings, only lazy ones — Many buildings have features that are best kept covered, such as harsh structural elements, service areas and storage facilities. Vertical gardens, with their wide range of size, shape, habit and leaf form can provide an elegant solution that is both attractive and functional. If properly designed and implemented, a green wall may help secure certain LEED credits. 
• Striking a pose — Interior space planning is a fashion-driven business, and nothing “strikes a pose” more handsomely than an artful living wall. Interior living walls bring nature in-doors, important especially in urban areas where the average person spends more time inside commercial or residential buildings than outside with nature. People are naturally attracted to plants and gravitate toward living walls where the sensory experience is captivating. Where else, other than the tropical plant houses of botanical gardens, will you see the variety of exotic and unusual plant species that can be found in some vertical gardens?

Longwood Gardens, one of the world's great gardens located in Kennett Square, Pennsylvania, created the largest green wall in North America as part of Longwood Gardens' new East Conservatory Plaza last year. The East Conservatory Plaza features a terraced lawn, lush new plantings and the largest indoor green wall in North America. This colossal vertical garden features a panel wall system across a green wall surface area of 3,590 sq ft (333 sq m) that includes more than 25 species of plants. "The East Conservatory Plaza embraces innovative landscape design, which captures the very essence of Longwood Gardens," said Longwood Gardens director Paul Redman. "The size and beauty of the green wall amazes and delights our guests as well as advances our continuing commitment to sound environmental practices."

If you have the green light to move forward on your living wall, keep in mind the following factors that are crucial to the garden’s longevity and success:

Location, location, location — The location of your living wall is significant. Not only from a visual standpoint but from a mechanical point of view, too. Is your desired location accessible to plumbing and electrical? What is the infrastructure of the supporting wall; is the green wall framing attaching to concrete, metal or marble? With the right infrastructure in place, nearly any location can be accommodated but the budget may be higher for a green wall location far from water lines and with no natural light for example. 

Survivability of plants requires appropriate lighting — Most interior living walls require supplemental lighting. Establishing healthy lighting for plants requires an experienced green wall professional who not only knows the light requirements of specific plant species but can perform light studies and collaborate with the electrician to specify fixtures to meet those requirements. Metal halide light fixtures and lamps provide the closest color temperature to natural sunlight and assist to promote photosynthesis, which is critical for plant survival. Adding photo luminescent sensors to the green wall is a smart decision as it can reduce the electric consumption. 

Plant selection is key — Your selection of featured green wall plants should be based upon microclimate conditions, plant growth habits, and the availability of light. An exterior north-facing wall requires an entirely different plant palette than a south or west-facing wall. For example, featured plants on exterior walls in the arid southwest climate differ from what can be used in the cold Midwest. Plants for interior walls are chosen to reflect low, medium and high light scenarios. Interior tropical plants require a minimum of 10-12 hours of at least 150 foot-candles (1,614 lux) per day to flourish. In a typical commercial hotel environment, there are on average about 30-40 foot-candles (322-430.5 lux) vs. 5,000-10,000 foot-candles (53,819-107,639 lux) that can be found outside on a bright sunny day.

Interior plants that thrive in low light of 75 to 150 foot-candles (807-1,614 lux) include the Scindapsus and Philodendron genus such as the Silver Satin Pothos, Neon Pothos, Goldon Pothos, Jade Pothos and Heart-leaf Philodendron. Medium-light thriving plants at 100-250 foot- candles (1,076-2,690 lux) include the Dallas Fern, Cretan Brake Fern, Rabbit Foot Fern, Begonia and Peperomia species. For environments with maximum light at 150-250 foot-candles (1,614-2,690 lux) plants such as the Alocasia Amazonica, Hawaiian Schefflera, Hedera Ivy, Purple Waffle Plants and Creeping Fig are ideal. 

The average person today spends about 90% of their time indoors with about half of the world’s population living in cities. Green walls improve a building’s air quality and enhance the emotional and physical well-being of the people who come into contact with it. Green walls act as acoustic barriers that can counter the noise pollution that plagues urban dwellers. Green walls harmonize buildings with nature and provide a living canvas for green wall professions to add the beauty of nature to any man-made structure. 

This article first appeared in Hotels www.hotelsmag.com