They plan their attacks carefully. They move stealthily under the cover of night. They leave no stone unturned. And when their attack is over, a neglected patch of earth has been transformed into a little garden.

This is the mission of Guerrilla Gardening, a group of urban warriors who will not rest until the crumbling corners of their world have been beautified. The nerve center of Guerrilla Gardeners is based in London, but thanks to the magic of the Internet, they've been able to enlist troops around the world. There are cells in New York, San Francisco, San Diego, and several other U.S. cities.

To make sure that their message is heard, they use their website to provide tips and tactics on how to launch a successful attack in your community. Thus far, their methods have proved to be very effective. Here's the basic blueprint of their attacks:

1) Select a neglected, orphaned patch of land in your neighborhood -- the uglier, the better.

2) Plan your mission carefully.

3) Buy some plants from the nearest nursery or DIY chain store.

4) Select hardy, cheap, colorful plants that are most likely to make an impact on the community.

5) Don't forget the arsenal, which includes homemade seed grenades (you can download recipes from their website), chemical warfare (generally natural fertilizers from backyard compost [0] heaps), and high-tech gear (rubber shoes so you don't get too muddy.)

6) Attack on a quiet night when no expects surprise weed clearing, soil amending and planting to happen.

7) Let your community know who's responsible for this random act of horticulture via flyers taped on nearby telephone poles or stop signs.