In a marginal corner of the garden, the previous tenant had questionable bonfires, which left a very deep layer of ashes, glass, metal, plastic and ceramic bits.
I have cleaned most of the coarsest waste left, and left the ashes, and now I would like to plant something on this area. Grass roots (Elymus repens) seem to take very long to migrate from the surrounding areas.
I thought I would refill part of the area (perhaps the size of a 10-litre pot) and plant a tree that could cope with the partially contaminated soil and perhaps even remove some of the heavy metals and other contaminants from the soil. Willow is the only candidate that comes to mind, but I am wondering if there are other options.
However, whatever goes in will have to cope with the surrounding contamination/high pH.