Green Guerillas, 1970's
What? A one page set of instructions to seed bombing, a tactic to add life, color and bio-diversity to vacant open space through guerilla seed planting. Authored in the 1970s by New York City's community garden group Green Guerillas as a guide to combatting urban decay, "seed green-aids" are cheap and easy to deploy, and yield unpredictable, but potentially beautiful, results.
Why? Seed bombs are such a simple idea and yet there are so many variations on the idea - from different seed bomb recipes to more complex guerilla gardening projects involving edible plants. It's a great starting point for thinking about neighborhood flora.