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Plants for green roof under a fir tree

aureliecelerieraureliecelerier Posts: 157
in Plants
Hi again, 
I have another question for today!
My husband and I are currently restoring a summer house that one of our neighbor kindly donated to us. 
After much deliberation we decided to place it at the back of our garden just under a large fir tree. 
As I have always been fascinated by the traditional houses of the Faroe Islands (see picture bellow) the big idea was to restore it so it would look a bit like this - stone foundation, wood painted in black, windows in white and most importantly a green roof. Above all i just wanted something that looks very natural. 
I really had my heart set on a grass roof but I have just realised that with the fir tree this might not be as straight forward as I thought it would be... 
Is there a specific type of grass that could grow well under such a big tree? Or any other plants that could be suitable (ideally evergreen...). I though about ferns as well. Good or bad idea??? 
Any help would be very welcome! Thanks


Posts

  • wild edgeswild edges Posts: 10,497
    How strong is the structure of the summer house and how much sun does the roof get now? Grass roofs are very heavy, even sedum roofs are heavy so first thing is to make sure the structure can take the weight. Have a look at the link below for weights.

    http://www.optigreen.co.uk/system-solutions/

    If you can keep your head, while those around you are losing theirs, you may not have grasped the seriousness of the situation.
  • aureliecelerieraureliecelerier Posts: 157
    Thanks for sharing this. Hubbie has already reinforced the roof but I am afraid I cannot tell you in details what has been done - I am the designer, he is the builder :smiley:) one side of the roof is full sun in the afternoon, the other part is moderate shade the whole day due to the fir tree. Layer height is 7 cm only and the roof is quite steep as well. 
  • wild edgeswild edges Posts: 10,497
    You don't make it easy do you :p I was going to suggest a moss roof but it won't like the sunny side. Moss can look great if you get the right cultivars and have the right conditions. Think Japanese gardens rather than the usual mossy council house roof you see around. Google Japanese moss roofs and take a look.

    I can recommend a book though which I've found really helpful and full of inspiring case studies and useful planting guides.

    https://www.amazon.co.uk/Small-Green-Roofs-Low-Tech-Homeowners/dp/1604690593/ref=sr_1_3?s=books&ie=UTF8&qid=1525294195&sr=1-3&keywords=green+roof

    A steep roof is good for drainage but not very good for stopping all the plants falling off so you'll need some kind of horizontal bars at intervals if you're not going to get pre-planted strips.

    This was my experimental sedum/alpine green roof which I imagine is a bit OTT for your taste but I was trying lots of varieties to see what would grow. Sedum acre or album (short green ones front left with white flowers) mixed with sedum rupestre would probably give you a grassy look for the whole year. Both are happy in sun and shade and are drought tolerant. They both spread quickly and are easy to propagate too.



    Detail pic before flowering. Sedum rupestre is the pine needle like plant at the front and sticking up at the back on the right. The red sedum to the left is also Sedum Album but the 'coral carpet' variety. Stick to just green as it looks quite patchy with the 2 colours mixed together. Most of the other varieties on there aren't evergreen.



    That small roof still took 3 bags of gravel and a bag of compost to give you an idea of the weight.
    If you can keep your head, while those around you are losing theirs, you may not have grasped the seriousness of the situation.
  • InglezinhoInglezinho Posts: 568
    This is a difficult one. I don't know if you noticed it, but there are no trees in the Faroes. Neither grass nor sedums will grow well in the shade of trees. I've never done this and neither imagine have the Faroese, but one of the best plants for dry shade, which is what we are talking about here, is ivy. There are a number of variegated forms with partly white or cream leaves, so it need not look dull. For a bit of fun try some hardy cyclamen, another good plant for dry shade but don't let the ivy swamp it. Good luck. Ian.
    Everyone likes butterflies. Nobody likes caterpillars.
  • NollieNollie Posts: 7,529
    Looks gorgeous, wild edges!
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • aureliecelerieraureliecelerier Posts: 157
    Wild edges, your green roof looks absolutely fabulous! 
    I never heard of Japanese moss roofs before, they are soooo gorgeous, totally my style  :)
    I really love the idea of using moss rather than grass but I understand it may not be the best choice, especially for the sunny side of the roof.
    However, I looked for moss alternatives and I found a ground cover rock plant called Sagina subulata (Irish moss, heath pearlwort). From what I read it looks like it could be suitable... But I understand it is rather invasive. Anyone know this plant?

    https://www.google.co.uk/amp/s/www.victoriananursery.co.uk/Amp/Heath_Pearlwort_Lawn/

    I also thought of dwarf Heather... Not my favourite choice but I suppose they would do well. I grew up in a town located in the middle of the Landes forest (largest maritime pine forest in Europe near the Atlantic coast) and I remember heather growing like weeds under the trees. 

    Ian, I also really like the idea of having cyclamen... They certainly would give a bit of colour in autumn. 
  • wild edgeswild edges Posts: 10,497
    Another moss alternative might be mossy saxifrage. I planted some small bits on top of a sunny dry stone wall a couple of years ago and it's thriving. It doesn't like to get too hot or dry so you may need to add irrigation or try a few varieties of saxifrage that are more sun tolerant, some of the spreading encrusted types maybe. Photo below is after planting in 2015 and the bottom one was last spring when it flowered (the pink and white flowers).





    If you can keep your head, while those around you are losing theirs, you may not have grasped the seriousness of the situation.
  • aureliecelerieraureliecelerier Posts: 157
    I love your rockery :o What a great little corner for the wildlife! Thanks for the suggestion, I think mossy saxifrage is beautiful too. It certainly is food for thought. I may have to ask the roof builder for his preference too before making the final decision :) Hopefully the summer house will be finished in the next few weeks. I will definitely post some pictures when it is. I know it is going to be a lot of work but it is also very exiting! Besides I have watched too many series of amazing spaces to have a conventional B&Q summerhouse  :D
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