One of our first tasks this semester was to identify potential plants for replanting two of the modular green wall systems in our experimental setup. Last year, we replanted wall 2, the one with the pockets I dislike so much, and
One of our first tasks this semester was to identify potential plants for replanting two of the modular green wall systems in our experimental setup. Last year, we replanted wall 2, the one with the pockets I dislike so much, and now it is time to select plants for walls 1 & 3. I’ve found that I enjoy the process of researching and identifying potential plants for use in green roof and wall systems, so I wanted to use this space to enumerate some of the more crucial aspects of the process. These include characterizing the site, identifying required plant traits, and then searching for a match.
The first step in the process is identifying the microclimate that the wall system will inhabit. In our case, since we are working on walls installed on the exterior of a building, the regional climate plays a large role in this. Many living walls you may see on pinterest or wherever may be inside buildings, and for those, local exterior conditions may not be as important. In our case, however, it is important that the plants are hardy enough to survive in the climate of central Texas. That means USDA Hardiness Zone 8B.
Microclimate, of course, implies that there are smaller-scale climactic variables that affect the walls. These include things like sunlight and wind patterns that are affected by the built context of the site. All of our systems are mounted on the south facing walls of a rooftop enclosure on top of the Langford architecture complex here at TAMU. The other walls of the enclosure provide wind shelter for the site, but also affect levels of shade throughout the day.
All of these considerations are further refined by the differing designs of the systems themselves. These vary in terms of plant positioning, substrate depth & composition, and irrigation design. For example, Wall 1 uses modules with 8 compartments that project out from the wall at a slight upward angle, maybe 30 degrees. The slots in bottom dividers allow irrigation to trickle down from module to module, and the plants g