Perennials are increasingly being used in vertical plantings. We’re seeing more and more of these living walls full of perennials appearing in our streetscapes. Keeping a number of their requirements in mind, many kinds of perennials are suitable for this purpose. Densely developed parts of the city are particularly good locations, since these plantings can contribute to a healthy living environment there. From providing natural air-conditioning to reducing noise.
- The release of water vapour from their leaves has a cooling effect.
- Since these living walls warm up more slowly during the day, they release less heat at night.
- Their leaves improve air quality by absorbing CO2 and pollutants in the air such as soot, particulate matter and nitrogen oxides.
- Walls covered in plants absorb 2.5 to 3 decibels of sound, so they reduce street noise.
- And they also enhance biodiversity.
The structure of a vertical planting using perennials consists of facade panels for holding growing medium and also an irrigation system for watering and fertilising. New systems making use of new materials and techniques are frequently becoming available. The wall is densely planted so that little if any of the supporting structure is visible. This provides a beautiful finished look as soon as the installation is complete.
Sun and shade
Many kinds of perennials can be used to cover living walls. The choice depends on their growth habit and the number of hours of sun they will receive. Good choices for a sunny wall would include Bugleweed (Ajuga reptans), Cranesbill (Geranium), Lamb’s Ear (Stachys byzantina) and Fountain Grass (Pennisetum ‘Hameln’). Deer Fern (Blechnum spicant), Elephant-eared Saxifrage (Bergenia), Lungwort (Pulmonaria) and Coral Bells (Heuchera) are just a few of the perennials useful for a shady wall.
The facts Installing living walls requires professional expertise. Since they have to be checked weekly, green walls supported by facade panels are not exactly low-maintenance. Nevertheless, their advantages for public green spaces more than outweigh their costs.