In a city best known for moody weather and moody philosophy, it's rare to find smooth concrete underfoot. Copenhagen may have changed since Kirkegaard's famous strolls, but the streets of this friendly and walkable city are a lesson in how to let water flow back to its source: inspiration for those planning new patios, walks, or driveways. To the right, river rocks are arranged around a tree; when the tree grows, the rocks can be removed to make room for the trunk, and plenty of water can get through to nourish the tree's roots; this solution is much more sensible than a heavy iron grate, and it protects the ground around the tree from getting compacted.
The few inevitable weeds poking through visually soften the stones. If desired, they could be easily removed by hand or with a garden torch, but why not just let them grow?
Plastic grids create a walkway through grass and insure against erosion here, where a creek lies to the right. The placement of the walkway and boulder creates a halfway point between the hard, modern lines of the building and the naturalistic landscaping of the creek.
Truly green design turns the inevitable into the beautiful: wear into patina; or here, weeds into edging: no herbicide required.