by Dil Green
We have a great site (800 sq m) in Clapham, that has lots of established trees, where we hope to build an eco-building etc. There is scheme for enough building to accommodate our needs that retains most of the trees, but we are looking to do more than that: we are not going to create any real 'playground' type spaces - there is enough blacktop in the city. Instead, we want to retain and enhance the existing character of the site as paths through a wooded area, and our thought is to work along the lines of permaculture 'forest gardening'. Unfortunately, no-one involved has enough experience to take this forward confidently, so we need advice!
As well as the site design, we have a more immediate need for advice, which might well be possible without a site visit. I've attached some 'photos of a rammed earth tyre wall we have begun building along the boundary of the site. The first photo sets the scene: we have a very busy and NOISY train line along the full length of the site. We need to control noise, which needs firstly, mass; BUT we can't do trench foundations for fear of harming the tree roots. So we came up with rammed earth, stabilised by the tyres (the wall may be up to 2m high in places). Houses called 'earthships' are built with a variety of this technique, if you know of them.
In case you are concerned, there has been a fair amount of research on possible contamination from old tyres, but by reassuring our situation has whole tyres above the water table, this most importantly and significantly reduces exposure of metal internal wires to the water.
The idea is to plant into the wall on the railway side (which faces SW), using a variety of species, for which the following characteristics will be important/valuable (not all will have all characteristics!)
We can think of some obvious plants: buddleia, ivy (various), wild strawberry, dog rose, 'old man's beard' (wild clematis)... but not enough.? This view shows the tyre wall in construction, the train lines are beyond. The wall is threaded between trees. The inside will be earth plastered - over some sort of mesh, we will then cut pockets into that and plant things like wild strawberry and other berries.
The next picture shows a detail of the outside of the wall. Mesh across the front will hold pockets of topsoil rammed into the triangular gaps between tyres - we will plant into these. Other planting locations are the ground in front of the wall (the line of the wall curves in and out to get past trees - some are outside, some inside), and the top of the wall - top tyres can be entirely filled with topsoil.
For an idea of scale, we have more than 30 metres of wall, around 1.8 - 2 metres high. doing the numbers, this means around 450 triangular pockets of earth (say 20 cm each side, and 20cm deep: roots can get into the soil inside the wall as well), and around 45 tyres along the top. So we need a great deal of variety - partly to make it look good, partly to make sure that there is variety to cope with some inevitable failed choices and varying weather conditions, and partly to be a haven for wildlife - once built, there will be no reason for people to be on that side of the wall.
We are keen to get some plants in asap - so that we have something to show this summer. Can you help?
Dil Green
A full list of plants can be downloaded here