For grand design plans, Urban Greenery is a pleasant site for beautiful, big ideas.
The RHS are leading the research in to the benefits of front gardens. See their website and research findings, Benefits of urban planting.
If you see the benefit of gardening, but have no garden to call your own, how about finding a little unloved patch of earth and planting it up? Read Guerrilla Gardening for some inspiring stories from around the world, and see their Facebook page to see upcoming events, including the Northern Hemisphere tulip planting event on the 11th October. Many in our community are already planting flowers in tree pits on our streets. (Just don’t plant anything invasive, or that you will miss too much if it gets squashed, and don’t damage the tree roots.)
How about joining Exchange in Roath? Many perennial plants or offshoots can be divided now, giving you extra plants for free. Take these plants or any other spare seeds or gardening equipment along to the drop off points, and turn up for the swap event on the Saturday. You can help other budding gardeners to grow plants for free. These could be used for a Guerrilla gardening event near you, or to cheer up your front garden.
What could you plant in your front garden or at the front of your house to benefit the neighbourhood?