Here are some photos of ordinary gardens in Berkeley, California. I was visiting recently and just took these snaps as I wandered around the town. Berkeley has a temperate microclimate and so has a long growing season and very little frost. It is warmer and sunnier than Britain, which also has a temperate climate, and gets drier in summer, but rarely very hot. If you travel just 15 miles inland the temperatures can start to soar, especially in summer. I love to see the effort that the householders go to here.
This does rather blow my Americans-don’t-garden hypothesis, I have to admit…except for the last one.