The Lily and Flower Bed, Take Two

Last year, I readied a patch for my wife to plant lilies and other flowers, partly for decoration purposes, partly to have plenty of flowers to pick and put in vases inside.

It was my intention to line the bed with boulders, but before I could do so, my wife had filled the bed with flowers, without leaving the 15-20 cm along the edge necessary for placing the boulders.

I have now decided to extend the patch out to the tree (the one to the left above that I have placed some of the boulders around on a temporary basis), and then place the boulders before anything gets planted.

I could not simply clear another 15-20 cm along the edge for placing the boulders, as it would not leave sufficient space between the tree and the boulders for my lawnmower to pass,