When I was a child, my grandfather grew intoxicatingly fragrant rose bushes, spaced one metre apart. I would follow him around the garden as he potted about. He carefully maintained a surface of crumbly, bare soil underneath the bushes, with a very neat straight border between the bare soil and the thick grass. He believed this was good for both the soil and the plants. Such practices reflected conventional wisdom at the time. Today, there is a growing understanding that soil