Patrick Blanc green walls are beautiful – but are they sustainable?

Patrick Blanc has made a great contribution to the technology of green walls, with beautiful results. But do they make useful contributions to environmental and sustainable design objectives? I do not know and would like to hear of any scientific evidence and environmental impact assessments. My guesses are (1) Patrick Blanc’s green walls use more energy for pumps/materials/manufacture than they save through insulation (2) more of Patrick Blanc’s green walls use tapwater than use rain which has fallen on the site (3) Patrick Blanc’s green walls make useful contributions to noise attenuation and dust capture (4) the contribution of Patrick Blanc’s green walls to biodiversity is negligible (5) one could achieve more environmental benefits, though less beauty, by using climbers.
The above example is on the Athaneum Hotel in Picadilly, London.
Stephen Alton shares my scepticism.

27 thoughts on “Patrick Blanc green walls are beautiful – but are they sustainable?

  1. Adam Hodge

    Is this an appropriate question? Surely the reality is that green walls are another containerised form of planting, rather like Window boxes, raised beds, huge planters for trees and shrubs etc and are principally for extending the decorative and greening effect of plants in an urban situation, all of which rely on imported water for their sustenance and longevity. To ask therefore if some large trees in planters are sustainable doesn’t really make sense. I don’t think it makes sense to ask whether green walls are sustainable ?

  2. Tom Turner Post author

    I suspect and fear that your comparison with window boxes is spot on – but there are many counter-claims regarding the ‘sustainability’ of Patrick Blanc green walls:
    Eg1: “Not only are Patrick’s vertical garden installations captivating, but also by putting these sustainable pieces in cities we are able to cut down on greenhouse gas emissions and have them act as a natural air purification system,”
    Eg2: “Green walls are firmly becoming entrenched in sustainable design, evidenced by high media attention, as much for their green properties as for their edible gardening possibilities. We’ve had tons of news articles posted in NewsLinks, our huge database of global articles, concerning living walls and green façades! In fact, they were listed as #31 in TIME’s 50 Best Inventions of 2009 and Triple Pundit recently proposed: ”Gardens Grow Up: Are Vertical Landscapes the New Green Roofs?“ – both featuring the works of Patrick Blanc.”
    Eg3: “Creator of “les murs végétal”, or vertical gardens, the French artist and botanist Patrick Blanc, claims that they aid a building’s energy efficiency, as a layer of air is created between the structure that the plants sit on and the building’s façade. This keeps the building cool in summer and warm in winter, reducing the need for artificial heating and cooling systems.”
    I am not rejecting these claims but I prefer scientific analysis to unsuported prejudice.

  3. Adam Hodge

    Perhaps the walls should be planted with drought tolerant plants that can survive without supplementary irrigation or with rainwater collected from the building.
    I am always astonished at the rich vegetation when walking in mid summer on the Turkish coastline or Greek islands..shrubs etc growing into soilless rocks with minimal available moisture, and am intrigued that so many of our current and previous plant collectors have found plants in such austere conditions, often arid.
    Perhaps the architectural world should challenge the green wall men to create plantings that are water self sufficent !?

  4. Adam Hodge

    I wonder if one could find some benevolent fund or charity, architectural firm or buildings material manufacturer to underwrite a competition for horticultural colleges to create the most beautiful and self sufficient permanent living wall. It would be fascinating to watch the young minds come up with clever new ideas that actually worked !

  5. Tom Turner Post author

    I am much in favour of experimentation (and competitions) but am also willing to hazard a guess at the likely findings:
    – The traditional climbers (eg Hedera helix and Parthenocissus quinquefolia) can supply all the sustainability benefits Patrick Blanc boasts of
    – Ivy and Virginia Creeper fell from popularity because of the damage they can cause
    – Modern concrete walls are not damaged by climbers
    – The only advantages of a Patrick Blanc green walls are aesthetic
    – Blanc is an artist with botanical knowledge, not an environmentalist

  6. Adam Hodge

    For my money I am in favour of the artistic creations Le Blanc much more interesting and attractive than a wall of either Hedera or Parthenocissus. If it can be developed to be less reliant on copious amounts of water then we are all winners !

  7. Christine

    Perhaps it is a matter of function following form….if Adam keeps insisting on beauty and Tom on function!

  8. Tom Turner Post author

    I aim to follow Horace’s precept from the Ars poetica:

    Utile quimiscens, ingentia Rura,
    Simplex Munditis ornat, punctum hic tulit omne.

    He that the beautiful and useful blends,
    Simplicity with greatness, gains all ends.

  9. Adam Hodge

    et ait germinet terra herbam virentem et facientem semen et lignum pomiferum faciens fructum iuxta genus suum cuius semen in semet ipso sit super terram et factum est ita
    et protulit terra herbam virentem et adferentem semen iuxta genus suum lignumque faciens fructum et habens unumquodque sementem secundum speciem suam et vidit Deus quod esset bonum

    And God said, Let the earth put forth [tender] vegetation: plants yielding seed and fruit trees yielding fruit whose seed is in itself, each according to its kind, upon the earth. And it was so. The earth brought forth vegetation: plants yielding seed according to their own kinds and trees bearing fruit in which was their seed, each according to its kind. And God saw that it was good (suitable, admirable) and He approved it.

    Genesis 1 v.11,12

    It could even apply to a wall of a building…..perhaps !!

  10. Tom Turner Post author

    Some ancient texts give me an even better feeling than archaeological remains – and it may be that when the Cities of the Future are as vegetated as they might well be we will have canopies of luxuriant vegetation and rich wild life above our heads. This is from the Oxford Electronic Text Corpus of Sumerian Literature, Inana and Ebih:

    121. jickiri6 mu2-bi kurun im-la2 giri17-zal im-du8-du8
    122. jic mah-bi ur an-na ni2-ba u6-di-de3 ba-gub
    123. ebihki-a jic an-dul3 pa mul-mul-la-ba ug tab-ba mu-un-lu
    124. ceg9 lu-lim-bi ni2-ba mu-un-lu
    125. am-bi u2 lu-a mu-un-gub
    126. tarah-bi ha-cu-ur2 hur-saj-ja2-ka e-ne-su3-ud-bi im-me

    121-126. “Fruit hangs in its flourishing gardens and luxuriance spreads forth. Its magnificent trees, a crown in the heavens, …… stand as a wonder to behold. In Ebih …… lions are abundant under the canopy of trees and bright branches. It makes wild rams and stags freely abundant. It stands wild bulls in flourishing grass. Deer couple among the cypress trees of the mountain range.”

    But in early 21st century CE cities:

    265. uru2-ju10 u8 zid-gin7 ba-ra-ma-lu sipad zid-bi ba-ra-jen
    266. urim2ki u8 zid-gin7 ba-ra-ma-lu kab-bar-bi ba-ra-jen
    267. gud-ju10 tur3-bi-a ba-ra-mu-un-cub mu-lu-bi ba-ra-jen
    268. e-ze2-ju10 amac-bi-a ba-ra-mu-un-cub na-gada-bi ba-ra-jen
    269. id2 uru2-ja2-ke4 sahar ha-ba-nijin2 e2 ka5-a ha-ba-an-du3
    270. cag4-ba a zal-le ba-ra-mu-un-de6 mu-un-kud-bi ba-ra-jen
    271. gana2 uru2-ja2-ke4 ce ba-ra-ma-al mu-un-gar3-bi ba-ra-jen
    272. gana2-ju10 gana2 jical-e ri-a-gin7 mul-gana2 bil2 ha-ba-mu2
    273. pu2-kiri6 lal3 gurun dirig-ju10 jickici16 kur-ra ha-ba-mu2
    274. edin giri17-zal-bi du3-du3-a-ju10 gir4-gin7 ha-ba-hur-hur

    265-274. “My city no longer multiplies for me like good ewes, its good shepherd is gone. Urim no longer multiplies for me like good ewes, its shepherd boy is gone. My bull no longer crouches in its cow-pen, its herdsman is gone. My sheep no longer crouch in their fold, their herdsman is gone. In the river of my city dust has gathered, and the holes of foxes have been dug there. In its midst no flowing water is carried, its tax-collector is gone. In the fields of my city there is no grain, their farmer is gone. My fields, like fields from which the hoe has been kept away (?), have grown tangled (?) weeds. My orchards and gardens that produced abundant syrup and wine have grown mountain thornbushes. My plain that used to be covered in its luxurious verdure has become cracked (?) like a kiln.”

    PS to be fair, we still have the tax-collectors!

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  12. Dana

    I’m actually building a vertical wall myself, one on a much smaller scale than patrick blancs(1.2x1m)..and I planted some perennial edibles, along with drought resistant plants native to Lebanon. The point of my project is to contribute to biodiversity, and to create a semi self sustainable wall that can be hung on a balcony wall. Therefore I am with Adam in that combining the two brings out a much better result, and is also aesthetic (not as beautiful as Patrick Blancs though). I’ll make sure to post a picture when its done 🙂

  13. paul exall

    We are just about to build our first green wall today, for a hotel in central Manchester.It will have edible plants, herbs and flowers to go to the kitchen! After a fair bit of research we are going with the patrick blanc model of building and some vertical hanging felt tubes. On the sustainable side we found the corrugated plastic for the backing though the felt underlay was shop bought it is from recycled materials, wool and synthetic but in theory could be got from a carpet fitters as they pull it out from under old carpets, dusty but maybe good.The frame to house it in is 2 by 4 pine and was saved from going to landfill by me jumping in the skip and grabing it.Our wall will be will be fed by a rainwater butt and with worm and green manure teas for food, also supplied by the pump. The pump is the main expense and the most potentially unsustainable thing there but could be done away with if there was a tank at the top of the wall so fed by rain,hand and gravity (easy).
    We hear a lot of talk about sustainability but when we get together as friends and do a bit then we can realy talk about it! for i as a artist and potential green wall roof expert see the city as green in my minds eye and how it would feel… Lets push each other up rather than drag down, do a bit and give suggestions after we have thought and figured out a bit for ourseleves…Those that do do!

    1. Tom Turner Post author

      Thank you for the information and good luck with the project. I love green walls and want them to succeed. Please keep us informed about the progress of your project.

  14. David O'Neil

    I have a major client with several large distribution / logistics “shed” developments in planning where we want to find commercially achievable “green walls” so the building can be part of a gateway to a city and not so much a steel wall. Any examples would be welcome! Please reply to

  15. Paul Exall

    We have been working on green walls for the last 2 years and tried hydroponic with not much success and have now settled on a fully organic soil based medium and are very happy with the results so far 6 weeks into the installation at a campus in Manchester metropolitan university.
    Its decorative rather than edible and is looking very happy. Now working on some outside designs that can be edible also…
    We have found with the plants used and special soil medium we grew that only a small amount of water is needed though will increase in the summer.
    I find we and the plants are much happier with soil as apposed to hydroponics. Its natural and most sustainable as there are no petro chemical inputs as far as feed goes. Its the way ahead…
    Just getting the web site up. Anyone that is interested please comment and leave contact details and we will get back to you with pictures and details.

    1. Tom Turner Post author

      I am very glad to hear of this research. My own experiment with a lightweight vegetated green roof is that it can flourish with rainfall for most of every year and for some of the occasional wet year. But it normallly needs some water if there is a long hot dry spell.

  16. Paul Exall

    Thanks Tom,
    Our plants are taking about 40ml a day at the moment and seem very happy with that, though we do leave it dry for 2 days of the week. We use Bokashi soil, EM Technology, that we produce ourselves and bio-char to hold water and give a slow release of the organic feed we charged it with, while at the same time making the mix lighter and more aerated.


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