There is a great piece on Salon by Will Doig about the way our parks are being over-designed and nature is being squeezed out. He makes a great argument for 'boring' parks where people can make their own fun, rather than a managed series of events with little room for spontaneity - or interaction with the natural world.
City planning already removes much accidental space, with the increasing privatisation of public spaces (anybody who has not read Anna Minton's Ground Control really should) and the proscribing of many activities. Doig says it is the parks from the 19th Century that offer the most unmediated experience, but even they are being gussied up. Fancy parks look great on the model and in photos but may be far less good for our mental and physical health.
I have always suspected that architects hate plants, because they are not controllable, grow in unexpected ways and even die. Now it seems that urban designers and landscape architects feel the same way.It is ironic if, just as we are coming to realise the importance of plants for well-being and there is a growing enthusiasm for vegetable growing and guerilla gardening alongside the new prevalence of green roofs, plants should be squeezed out of our parks. Let's hear it for scruffy grass, a duck pond and a flower bed - for parks that won't win prizes but may just allow people enough relaxation to have some prize-winning ideas.