Green Walls and Winter Interest


By George Irwin, The Green Wall Editor
The Green Walls Column
March 18, 2011
Photos Courtesy of G-Space Design, Project Manager and Certified Product Installer




Green Walls can’t survive in the cold; they don’t look good in the winter; they are only viable in the south or indoors…..Think again!  There is more science behind a green wall than you may think.

I am long overdue for an updated article but was torn between two topics of interest.  I was set on talking about the latest profitable service for landscape contractors and garden lovers alike when the timing couldn’t be better talk about these green wall images I recently saw in a newsletter.  The winter interest is just as dynamic and provides incredible pallets of delightful colors.

What happens in the winter?  Read on my friends and lovers of vertical bliss.  It’s time to put an end to the banter about green walls and winter.  Not only can they survive, they can be gorgeous!  I was reading the newsletter from Michael and Angela Bucci, owners of Philadelphia based G-Space Design and Philly Green Wall & Roof where they featured multiple walls that display just as much interest in the winter as they did in the spring and summer.

The wall below is one of many at this particular location in the Philadelphia area.  I enjoyed this wall the best, with the enhanced purple and red ground cover providing an accent to the blue in the wall.  The transitioning from late fall to winter is undeniably just as interesting as the blue becomes brighter and the purple gets more intense, all while retaining a green surround.

Photos Courtesy of G-Space Design

Philadelphia, PA Green Wall
Left, October 3, 2010; Right: January 6, 2011.

The success of the wall is all about knowing how the plants react in their geographic region and elevation.  Specifically, the Mondo Grass keeps a green color, tips have browned; Hosta Francine is completely dormant, all leaves have browned; Blue Star Juniper turns a bright slate blue color; Lysimachia aurea has some brown and drooping leaves; Huechera Purple Palace displays bright purple, Purple Phlox has some green retained and the Sedum ternatum shows bright green color all winter.

Without disclosing all the science behind the success, I will tell you that much of what we see here is due to preventative maintenance.  This is not to say there have not been extensive trials and, in fact, mistakes.  Some plants simply don’t provide winter interest, like the hosta or other perennials.

Below is the noted PNC Bank, still the largest exterior wall in North America and by far one of the showiest as the color variations provide both texture and contrasting variations as the seasons change.

Photos Courtesy of G-Space DesignPhotos Courtesy of G-Space DesignPhotos Courtesy of G-Space Design

PNC Bank, Pittsburgh, PA
Left: September 16, 2009; Middle & Left: 1st winter 2010.


Photos Courtesy of G-Space DesignPhotos Courtesy of G-Space DesignAjuga 'Black Scallop'
Carex 'Evergold'
Huechera 'Purple Palace'
Lysimachia aurea
Sedum ternatum

PNC Bank
Left: September 2010; Right: 2nd winter February 23, 2011.

When we teach maintenance, it’s not so much the amount of pruning and time on a lift or ladder (I wrote about maintenance in October of 2008).  Besides having access to the wall, following a standard irrigation checklist and keeping the catch basin clean, the preparation for the winter is one of the most important maintenance visits throughout the year.

Unlike plants in the ground which are protected by snow, mulch, and other wind deterrents, green walls are subject to harsh conditions yet the plants are unlike traditional sedum for green roofs and are susceptible to the enhanced and harsh conditions of winter.  Much of the decorative walls are not sedums and can be very delicate, making them susceptible to the harsh winds.  Wind tears at leaves and removes moisture from both the plant and the growing media.  The key is to prevent the plant from losing moisture during the winter months.

We protect the green wall from moisture loss two ways.  The first is a trade secret, but the second I’ll gladly disclose and say that periods of warming provides an ideal time to irrigate the walls in the winter.

YES….the irrigation should be turned on when there are breaks of warming from 35 degrees or higher.  Microscopically, the roots are seeking water during these times and without it the plant will die.

Photos Courtesy of G-Space DesignPhotos Courtesy of G-Space Design

Philadelphia Gateway Project: Summer of 2010

Dwarf Mondo Grass - mostly brown, some green at base of leaves
Sedum rupestre 'Angelina' - reddish orange color
Sedum 'Blue Spruce'
Sedum album 'Red Ice' - reddish color

Photos Courtesy of G-Space Design

Philadelphia Gateway Project: February 8, 2011

It has been a thrill to be part of an industry where there is a handful of successful science based green projects.  On the other side, it is the new opportunities to create jobs and provide the next new paradigm shift in technology that is exciting.

Planting a wall and hanging it are only the beginning.  There is science behind success.  The failures could be linked to many variables including product, growing medias, plant choices, irrigation and much more.

I feel there needed to be some clarity on the subject that not all green walls - and the experience behind them - are linked to the industry as a whole.  Not all green walls can survive the winter, however, many can while providing much needed winter interest from the living, breathing, plants.

George Irwin, The Green Wall Editor

George Irwin is the President and CEO of Green Living™ Technologies, LLC (GLT) based in NY.  Green Living™ Technologies is the only U.S. manufacturer of growing media based green wall and three types of green roof systems.  Mr. Irwin is a former trainer for Green Roofs for Healthy Cities Green Walls 101.

Contact George Irwin at:,,, or 1.800.631.8001.

Past Green Wall Articles

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