Last month, while exploring the historical centre of Mexico City, I came across a stunning example of an outdoor green wall – in an alleyway. Planted with sedums, sempervivums, vines and flowers, the warm climate allowed for a diverse range of species, and the wall was thriving.

Though local restaurant owners told me the green wall had been built by the municipal government, there was no information posted about it’s design or purpose. It was likely built as part of Mexico City’s Plan Verde. According to the municipal government website, Mexico City has plans to attack the issues of air quality, water scarcity and climate change though a series of ambitious projects. Green walls and roofs are one aspect of the plan, but the idea has been controversial because of the high cost of green roofs. Plan Verde also includes plans for new bus and subways lines and extensive bike pathways.

The plants were in what looked like heavy duty nursery containers attached to the wall. They were watered daily via a hidden irrigation system.

The wall was really surprising in the heart of a city renowned for it’s smog, but the people working and eating around it didn’t show much curiousity, and no one seemed to know why it had been built in a small back alley near Avenida Cinco de mayo and Calle Palma. It’s too bad that the Mexico City government hasn’t put any signage near the green wall, as it would be a great opportunity to educate people about sustainable technologies. However, it looks as though environmentalist’s worry that Plan Verde would be stymied by “lack of public outreach” could be valid.

This segment about the Heatley Avenue green roof and it’s benefits will air on television screens across the United States on the show VJIam this week.

If you want to find out when you can view us, here’s the show schedule, and thanks for watching!

CBC News Vancouver at Six did a piece that highlighted Eclipse Awards Ltd and the Strathcona Business Improvement Association’s efforts to go green. Shots of the green roofs on 121 Heatley and the Eclipse Awards building on Alexander were featured in this segment.

To see Erika Richmond Design in the news, click here.

The next step was to add the growing medium. So one wet morning we used a mulch blower to lurch it all up there:

Mulch blowing the growing media two stories up

I had to rake the growing media out. The media is a mix of organic matter and lightweight aggregate.

Shoveling the growing medium

Here is the roof mid-planting. Parts of this green roof are six inches deep, so we can grow plants that have deeper roots than sedums, such as Irises and Fescues.

Alexander roof during planting

When I visited the roof of Eclipse Awards Ltd on Alexander Street this summer, it looked like this:

Alexander Street roof in summer 2008

The roof was quite old, and in order to make the building more energy efficient, Eclipse Awards replaced the bitumen roof with a white roof  (thermoplastic polyolefin [TPO]). Instead of absorbing sunlight and heating the building, like a black roof does, white roofs reflect sunlight back into the atmosphere, and they don’t transfer nearly as much heat into the building. This should help Eclipse Awards save substantially on their cooling costs in the summer. The three skylights will let in natural light, which will also help save energy and money.

In addition, Eclipse Awards wanted to add a small green roof to act as a demonstration for other businesses that might want to adopt this technology. The first step was to build the frame and line it with a drainage layer:

Alexander in progress

Back in February 2008 I worked with an Environmental Youth Alliance colleague to design a perennial garden on the YWCA of Greater Vancouver’s rooftop. YWCA Operations Manager Ted Cathcart and a crew of volunteers have been growing vegetables on the 4-story roof in downtown Vancouver since 2006. This summer they wanted to add plants that would be highly productive, but would require less maintenance than annual vegetables. We chose to plant raspberries, (non-invasive) blackberries, strawberries, blueberries and kiwis. All the food goes to the Crabtree Corner Family Resource Centre, so we chose popular fruits that the women and children would be happy to eat. Engineering students from UBC built this trellis for the berries:

Three rows of berries at the YWCA

Berry guard

Mason Bee Condo

The YWCA is part of the Mason Bee Vancouver project. The garden provides a home for Blue Orchard Mason Bees, a native, non-aggressive species which pollinated the rooftop garden and surroundings all summer.

Here are some more photos of the Covenant House as a finished rooftop, with the Dominion building and the new Woodwards in the background. Once upon a time, the Dominion was the tallest building in the British Empire…

Notice the pigeon spikes.

Some details:

We restored and treated the old cedar boxes, replacing much of the wood

Fence Detail

The old and the new. Notice the pigeon.

My second project was to restore an old rooftop garden on the Covenant House of Vancouver. The garden was built ten years ago and had become a hot spot for pigeons, but not for gardeners, or even Covenant House residents and staff.

Here is what it looked like back in June:

Covenant House Garden before renovations. Lots of weeds and damaged wood.

Half finished:

the old boxes in the background contrast with the restored boxes in the foreground

And here is what it looks like today:

Covenant House Garden in August

All the sedums were purchased as plugs from NATS Nursery in Langley and planted in June. These photos were from August, showing how much the sedums have spread in one summer.

sedums in the sun. Sedum divergins, a northwest coast native.

sedum rupestre 'Angelina', the Dr. Suess sedum.