I've lived in many places in the world that have a garden moniker. I went to university in the Garden of England (Kent). I spent a year and a half living in New Jersey, the garden state. Now I'm living in Lyttelton, which is a part of the city of Christchurch, which calls itself a garden city. Part of the reason for this is the wonderful Hagley Park in the centre of town. It has paths that are flanked by trees which look wonderful at this time of year.
What would be great is if Christchurch would plant more trees in avenues of roads. Trees do an amazing job of soaking up pollution and controlling temperatures. When I lived in Melbourne in Australia I was in a suburb that had lots of plane trees. The temperature in Elwood was about 5° cooler than the neighbouring suburb suburb of St Kilda, due to those trees. Trees are amazing.