There is a system based on plants growing on rockwool. Slabs of stonewool
of 7.5 cm hight are used to grow the plants. The plants need an automatic
water and fertilisation system.
A number of those planted slabs on top of each other will give you a
This system is used by the Grodania company, for planted soundwalls along
roads, but also inside buildings.
The Grodania company is represented by Roxsul company in Canada. Sorry,
but I dont have their phone number.