They’re illegal, carry out their deeds at night to avoid detection and are active in a growing number of cities around the world. They’re Guerrilla Gardeners. Their crime? Attacking ugly patches of public land with hand-trowels and flowering annuals in covert greening campaigns. Typical targets include roundabouts, verges and other neglected areas, which are beautified with plants. Richard Reynolds’ website has a global noticeboard of activities plus a how-to guide for beginners.

For the more timid green-thumbs among us (less guerrilla, more…pansy), there’s Permablitz. These little groups raid suburban backyards (with the residents’ consent) and turn lawns into edible gardens. Permablitz (as in permaculture meets backyard blitz) also has a noticeboard with upcoming events.