In this article, we look at how using ferns on the green wall can lead to some interesting results.
What do we know about ferns?
Well, you can read more about ferns here, but for the sole purpose of looking at how ferns can mess up your green wall, let us define ferns simply as one of the many types of plants that can be grown on a green wall.
Some characteristics of ferns are as follows:
1. Ferns are epiphytic. They grow non-parasitically upon another plant (such as a tree)
2. Ferns have roots (duh)
3. Ferns require little to no care, and they can survive in a wide spectrum of shade conditions
Looking at Point 1, we can imagine plants to be good at clinging onto stuff. In fact, so good that very often you can see lots of ferns covering the trunks of large canopy trees (Figure 1).
Point 2 would suggest really tough root-growth systems, since the survival of the fern essentially depends on how well they can establish themselves onto their host.
To summarise, ferns are hardy plants. In fact, their survival is virtually guaranteed when installed on the green wall. They are probably the Samuel L Jackson of green wall plants (Figure 2). Why Samuel L Jackson? Cos he’s tough, and you’ll always want tough on your side.
It’s all good, until we realise that in most films starring Samuel L Jackson, people are subjected to grievous harm, and there tends to be needless damage to property. Here, take 2 minutes to indulge in the awesomeness of this amazing badass actor.
Well, same thing when it comes to ferns.
Ferns, being ferns, will grow fairly well if irrigation and nutrients are provided for. Figure 3 shows how ferns can outgrow the confines of the green wall (white dash). Even when the substrate starts to show signs of deterioration, it has little impact on fern growth (Figures 3 and 9). It is interesting to note that during the first attempt at plant installation, there were a few varieties of plants on the wall. They included the following:
1. Hemigraphis alternata (Figure 5)
2. Portulaca grandiflora (Figure 6)
3. Nephrolepis acutifolia (Figure 7)
If you are confused by the latin (like me), do what I do and associate them with loveable characters from film:
1. Jonah Hill (Figure 4)
2. Michael Cera (Figure 4)
3. Samuel L Jackson (Figure 2)
Needless to say, 1 and 2 didn’t stand a chance. In a few months, we couldn’t find any Jonah Hills or Michael Ceras on the wall. All that is left were the Leroy Jacksons. Subsequently, all the plants were replaced with ferns.
Close-ups of the green wall are shown in Figures 8 and 9. Basically, the green wall consists of a solid foam that is sandwiched between 2 metal meshes. There are pockets where ferns are supposed to be planted into. Figure 9 is particularly telling, as we can see that the substrate is in pretty bad shape, yet ferns are still growing well when they are essentially feeding on nothing (Point 1, ferns are epiphytic). During inspection, the roots were observed to have outgrown the confines of the pockets and have established an intricate set of brown, messy, intertwiney sinew that is somewhat similar to what my mum would call char bee hoon. The roots were so overgrown that:
1. They binded the 2 layers of metal meshes and foam panel so tightly that removing the exterior metal mesh for maintenance was impossible without cutting the roots.
2. They stared growing on the concrete wall behind the vertical greenery system, making the surface vulnerable to root penetration and subsequent water proof issues.
Since regular maintenance was impossible, the maintenance crew opted to remove everything and replant the entire green wall.
Shrubs can be pruned, but roots cannot be maintained in a systematic and cost-effective manner. Not to say that ferns cannot be used on the green wall at all. What you can do to prevent this from happening to your green wall is to use ferns sparringly, as aesthetic highlights. A spot or two of Leroys wouldn’t hurt. Much.
There are also many other plants that are able to cover large areas without the need for much maintenance.
Once again, this is not a critique on the green wall system, but an objective assessment of the plants used using anthropomorphical references to Samuel L Jackson and the stars from Superbad.
For more information on the appropriate type of plants to use for your green wall, send an email to UGL @uglab.sg@gmail.com. Advice is free until you start asking too many questions.
– t
References:
http://en.wikipedia.org/wiki/Fern
http://en.wikipedia.org/wiki/Epiphyte
https://www.youtube.com/watch?v=x2WK_eWihdU
https://www.youtube.com/watch?v=XBj4D061UG0
http://whiskandknife.files.wordpress.com/2013/08/beehoonfg.jpg
Images:
2 – http://i1.ytimg.com/vi/x2WK_eWihdU/maxresdefault.jpg
4 – http://www.richardcrouse.ca//wp-content/uploads/2013/09/superbad.jpeg
6 – http://backyardgardeningadventures.com/wp-content/uploads/2013/02/20130224_095522.jpg
7 – http://www.agardenforthehouse.com/wp-content/uploads/2011/11/img_1339.jpg
