Off the Wall

Next time you are driving along Piccadilly in London's Mayfair district you may be taken aback by the installation of the vertical planted gardens on the side of the newly refurbished Atheneum five star hotel – they stretch from ground level up to the penthouse apartments on the 10th floor!  This is a signature piece of the now well known French botanist turned living sculptor that is Patrick Blanc, complete with dyed green hair and green finger nails.  He is the proclaimed grandfather and trailblazer of this fairly new trend for covering buildings with a variety of living plants.  His work can be seen in many of the most cosmopolitan cities around the world, many of which are in his home city of Paris where they have been established for a few years now.  The process is complex and works on the principle of hydroponics.  Small, practically soil-less plants are stapled onto a foam board and covered with a capillary blanket which holds them in place.  Water and a controlled diet of essential nutrients are then washed from top to bottom in a carefully controlled manner and recycled constantly.

The process is highly sophisticated and complex, but the effects are startling; a true "WOW" factor moment.  However they are incredibly expensive and near impossible to copy and down-size to a domestic scale.  But, like all good ideas, there is then a proliferation of similar processes that claim to offer the same effect.  These have mainly developed for commercial schemes but then can be tailored for private commissions.

Take the Westfield Shopping Centre which boasts the largest living wall in Europe.  It has a serpentine wall which runs the entire length of the shopping centre shielding it from Shepherds Bush.  This system uses a plastic tile system with pockets containing soil and plants known as the ELT system which uses a leak hose irrigation pipe to deliver water and nutrients via a simple dosage unit.

Another system also uses plastic tiles filled with horticultural rock wool (an inert blotting paper-like medium) and the small plants, again with no soil, are acclimatised in greenhouses before being installed at their final location.

Prices are not cheap.  £300 - £400 per M² will be the price installed and the planting can be adapted to suit most sites and climates.  It is amazing how many plants that will grow vertically given enough water and nutrients.  A ride down any country lane in Devon or Cornwall will show you how much will grow out of the natural walls you pass by.

Here are my top tips when planning you green wall:

• Think about the aspect of your wall and plan appropriately…if the wall is basked in sun for much of the day you will chose different plants to a wall in the shade.
• Try plants that naturally do well such as many of the ferns; for example Harts Tongue ferns, Maidenhair ferns and the smaller leaved varieties seem to do better.
• Heuchera, Bergenia and Euphorbia are also popular choices.
• Try sedum at the top where it is lighter and dryer with the more shade and moisture lovers lower down.
• Keep the planting bold in sweeps and drifts of single varieties
• Avoid using plants that will grow quickly and outgrow the space or any that require lots of pruning.
• Remember to keep an eye on the scheme once set up.  It should be trouble free but remember if the irrigation scheme fails so will the wall.  So the whole thing should be treated very much as you would do for window boxes or hanging baskets.

So, if you have struggled to get something to hide that ugly garage or utility area and want the latest horticultural chic – vertical planting could be just for you.

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