Green Wall Reboot

My green wall as it looked in 2016, 12 years after its installation. Note the mirror at the far end makes it look far longer than it really is.

By Larry Hodgson

Time to tear out an old living wall and put in a new one!

When I installed a green wall of cork bark in my bathroom in 2002, I predicted it would last 60 years. Well, I was wrong. It lasted about one third that long: 19 years to be precise.

In January 2021, a section of wall came crashing down, dumping plants, sections of rotting bark and organic matter (something which, for some reason, my wall produces prodigious quantities of!) into the bathtub below. Prying here and there, I was able to pull off more sections of cork. . . far, far too easily.

The fact of it was—and I already sort of knew it, although I was in deep denial—, much of the cork making up the wall was disintegrating. My beautiful green wall, the pride of my household, was coming to an end.

So, I decided to redo it. And write about the experience here.

Before the Fall

My green wall consists (I’ll use the present tense, as it is operating again) of a 7 ft × 7 ft (2.1 m × 2.1 m) wall covered in slabs of cork bark over which water drips every morning, thanks to a pump on a timer. A basin underneath catches excess water so it can be recirculated.

The bark therefore goes from moist to fully dry every day. . . as a tree trunk would in a jungle where there is a daily rainstorm.

Natural lighting in my bathroom is extremely limited. What little there is is largely supplanted by T5 fluorescent lights. (Had I started today, I would have used LED lamps.) They’re on a timer set at 8 hours a day. Yes, that’s not nearly enough, but the best I could negotiate with my wife, a late riser, who can’t stand the idea of stepping into a brilliantly lit bathroom first thing in the morning.

The wall is planted with epiphytic plants: plants that grow on trees in the wild. That includes aroids (philodendrons, rhapidophoras and pothos, mostly), ferns, begonias, hoyas, gesneriads, peperomias and a few others. Since the light intensity is medium at best and the day length so short, I’ve had no lasting success with the two best-known groups of epiphytes: orchids and bromeliads.

The plants wander about, rooting into the bark here and there, like epiphytes do in the wild.

Since the system is largely automated (watering, lighting, etc.), the main upkeep simply consists cutting back plants that are too invasive and picking up any fallen or yellowing leaves. I could easily go away for months, and it would take care of itself. No other garden I own requires so little care!

Usable Life of Landscape Features

While I was very disappointed by the slow failure of my precious wall, my son, Mathieu Hodgson, a landscape designer, was much more generous. “Even outdoor landscaping features—walls, stairs, etc.—are usually only good for 12 to 15 years. Then you have to redo them.” To his mind, a wall that lasts 19 years is actually doing better than average.

Knowing that was at least a consolation.

I’m only watering the new version once a day, and that may make a difference in durability. I watered the original twice a day for the first few years, thinking more water would be necessary to keep the plants’ roots, which are largely exposed to the air, happy. But that turned out to not be true. . . and may well have shortened the life of the wall. With just one session each morning, the wall will hopefully absorb water less quickly and therefore last longer.

The Reboot

There was another problem involved in redoing the wall this time around. And that is that I no longer have the health to do it myself. I’m now an invalid, suffering from a debilitating lung disease, and largely housebound. I can barely change a light bulb, at least not when standing on a stool, without coming close to fainting! Essentially, I can no longer do any physical work. At all. This project was now way beyond my capabilities!

Yet, redoing this wall is not a run-of-the-mill project I could simply hand over to a remodeling contractor. Most wouldn’t have any understanding of what I wanted to do. I mean, what would you think if you’re used to putting in Gyproc and paneling and someone wants to put in a cork bark wall with water dripping over it every morning? It just sounds crazy! Most home remodeling contractors wouldn’t even understand why anyone would want to grow plants on a wall! The three I contacted simply weren’t interested.

So, my son Mathieu stepped in. As a landscaper, he’s used to working with both tools and plants and I think I instilled in him some respect for the environment. So, I ordered in the bark (I found a supplier in Ontario: Exotic Feeders), then Mathieu came and stayed with Marie and I for a week as he worked on it.

He first removed the plants, pulling them free from the wall and tossing them into large clear plastic bags: sort of temporary greenhouses. (They looked like bags of mixed salad greens from the grocery store!)

Then he pulled off the remaining bark and scraped off any plant roots and silicone left on the wall. Finally, he repainted the wall with black sealant so water wouldn’t leak through. (That had worked perfectly the first time.)

Cork bark “flats” are sections of cork bark harvested from cork oaks (Quercus suber) in southwestern Europe or North Africa. They’re commonly sold as a support for growing orchids. They really aren’t as flat as the name suggests—most form something like a quarter moon when seen in cross section—and are certainly very irregular is shape. None are even close to being rectangular.

My order of 125 lb (58 kg) of cork flats contained pieces both big and small and an infinite variety of shapes. He had to plane the back of the bark pieces so that there was a flat enough surface behind them that it would stick readily to the wall. Then, using brown silicone sealant acting as waterproof glue, he assembled the pieces of bark like a jigsaw puzzle.

Minor Disaster

After a few days, the wall was deemed ready for use. Since the silicone was labeled “fast-drying” and the nasty silicon odor was fading, we figured it was ready. So, planting began.

That turned out to be a mistake. When we turned the water on to test it, several pieces of bark came loose: it turns out that, if the silicone along the edges of the bark was dry, that underneath the bark wasn’t. We cleaned up the mess and stuffed the cuttings back into their holding bags.

Mathieu delayed his departure long enough to replace the fallen bark pieces, then had to get back to his job. We decided together to wait a full month before “testing the waters” again to make sure the silicone really was dry!

As it turned out, he wasn’t able to return until 2 months later. During that time, I had tested the irrigation system several times and the cork remained firmly attached.

Finishing the Planting

Planting a cork bark wall is not what you’d think. I don’t use rooted plants, but rather cuttings. I tried unpotting plants the first time and the results weren’t that great. The plant always ended with messy roots dangling around in a very artificial way. It’s much more natural when they start from scratch, forming new roots that mold to the shape of the bark just like they would in the wild.

So, no messy repotting is required. You just need secateurs.

Stem tip cuttings or stem section cuttings just need to be wrapped in sphagnum moss and fixed to the bark. That can be either by working them into one of the numerous cracks and fissures or by fixing them anywhere with pieces of metal wire pushed into the bark. That’s all you need: epiphytes just love rooting into bark and it doesn’t require much to encourage them.

When the planting was done, we turned on the water again. . . and there you go: the wall was alive again! It’s been “running” now since late November 2022, so, for over 4 months now.

A Waiting Game

Within a few days, little nubs of roots began appearing on some cuttings; about a week later, so did new green buds. Then stems and leaves began to form and fully-formed roots started to show up. Soon stems began to lengthen as well. At least, that was the case with the most successful cuttings. Others took up to 4 months before showing any sign of life. And there are still a few I’m not sure of. Yes, and some did fail, unfortunately. But now the wall is filling it. Ever so slowly. I estimate it will take two years before it will look fully green again.

And the whole process gives me great joy.

The Joy of Watching

Any gardener knows the absolute happiness you feel as your little vegetable and annual seedlings grow from day to day as they become stalwart young plants. You just can’t help checking on them, over and over again. And the deliciously earthy smell that fills your nostrils when you lift that seedling dome or open that bag: it just oozes the feeling of life. When don’t they have that as a room freshener scent? Your heart just soars!

Well, the same goes for the wall cuttings.

I spend probably 30 minutes a day, in 2 or 3 sessions, just looking at the wall, noting every little sign of progress. When I brush my teeth, I don’t face the mirror, but the wall! I watch leaves unfurl, new buds poke out, and roots slowly creeping down the bark and through its crevices. I like to touch the wall and inhale its forest-after-rain perfume. I sometimes even press myself against it, as if to absorb some of its power.

Because, even as the wall comes to life, I am leaving it. I was told 6 years ago I had 1 to 2 years left to live and I’m still here. (Wow!) Still, I can feel the end clearly coming now. This wall will be my legacy. I’ll never see it fill in entirely, but I’m just so thrilled to see that Mathieu has helped save it and will help my wife to maintain it.

But gawd! Isn’t it just so beautiful! What a joy it brings me!

Photos by laidbackgardener.blog