We don't endorse vandalism. This is just something kind of amazing that's going on.
A few people who are disappointed with public spaces -- or maybe they just don't have room at home -- dig up medians and things under the cover of night and perform the dastardly deed of planting unauthorized tulip bulbs and so on.
Guerrilla gardeners use the cover of night to sneak towards their selected target, where they tamper with public property in order to . . . plant flowers, aid urban ecosystems, and improve the quality of life for people living in the community? Sounds like the most adorable form of vandalistic rebellion ever. And it is.
The gardeners undertake projects like planting sunflowers under storm grates, replanting weed-ridden street side planter boxes, and making botanical arrangements around trees lining city roads. Technically, guerrilla gardening is illegal, but there have been no reported cases of arrests, just some incidents where participants have been questioned by authorities. Some have initially been accused of engaging in terrorist activities--maybe someone confused planting the seeds of hate with the seeds of sunflowers.
Here's a news piece on one particularly brazen guerrilla gardener, via Craft: