The trouble with living green walls

Posted: 05/12/2014 in Green Walls
Natural rarely means easy. So natural green walls are not only fashionable, they are healthy and apt for both people and the planet. No argument there. But those who want to sign on to this urban ‘regreeneration’ should read the fine print. Like marriage, vertical planting is a long-term commitment. Living green walls need time, effort, attention, care and loads of love. They also require a fair sum of money.

There is simply no way around it – vertical gardens are costly, to build and to maintain. Moreover, they are quite complicated. You will need to consider issues such as weight and structural load, support, lighting, irrigation, waterproofing and ventilation, not to mention plant health and nutrition. A lush living wall will almost certainly have a keen professional team of horticulturists behind all the stunning verdure. Only the most persevering, obstinate, or time-endowed, can DIY it.

Even if the aesthetic and green benefits outweigh the drawbacks for many, people still need to be fully aware what, in practical, daily terms, having a natural green wall entails. The rightful enthusiasm for them should be balanced by a sober education on sustainable construction. Respondents to a study on the factors for opting for living walls spoke of underestimating costs and mechanical problems (leaking, lighting, pumps) as well as planting failures and difficulty of accessing areas, especially for sizable builds.

To start, a square meter of living wall will cost around GBP1,000 to install, which translates into hefty outlays the larger the project. Afterwards, one has to budget adequately for maintenance, which falls under many categories:

Establishment maintenance is needed for the first two years to ensure vigorous plant growth – pruning, weed control, irrigation.

Recurrent maintenance ensures appearance, safety and functionality, the routine tasks for upkeep such as pruning and picking up leaf litter.

Cyclic maintenance are infrequent, scheduled treatments to maintain infrastructure or specific components of the system.

Emergency maintenance is undertaken for component failures or unforeseen events like storm water incursions.

Then there is renovation maintenance when design failures require remedial action.

All these maintenance costs can add up and surprise if not properly accounted for. Likewise, Installation can be a cumbersome affair. One has to consider the weight and thickness of the modules, framework and plants in relation to the load-bearing wall. If the wall is of a certain height, installation can only be safely and securely accomplished by professionals.

Irrigation issues add to the complexity of the structure. As water interruption is a common cause of plant failure, the mechanism for water delivery needs to run smoothly and efficiently. Some systems are automated and remotely controllable, others are highly specialised, requiring monitoring of pH levels and water hardness, as those for hydroponic systems. A water meter is needed to monitor irrigation volume while a pressure gauge ensures the even application of water. Pumps are necessary for constant irrigation and water recycling. You can imagine the increased chances for failure of your living wall with all these considerations.

Failure rates also rise with disease and pest infestation. One has to closely watch out for spiders, aphids and beetles that bore holes or eat into leaves. External walls are prone to weed growth. Root rot is caused by water moulds (and excessive watering).

And, then, if you are unfortunate enough to be saddled with a badly designed scheme, such as inappropriate plant selection, density and decorative patterning, you face the prospect of unsightly bareness and a lifeless wall, especially during winter. Definitely not the robust green sensation you had hoped for.

The trouble with living green walls

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The trouble with living green walls