Tony Minh Nguyen is a designer, woodworker and (relatively) recent graduate of the Savannah College of Art and Design. His first commercially available project, the Flower Grenade is available right now through Suck UK. The "bio-grenades" were originally developed out of molded paper pulp and filled with soil and flower seeds. The commercial versions appear to be made of clay.
The idea is kind of similar to knit graffiti...a random act of senseless beauty that can improve the urban landscape...while making you feel like a badass. Maybe Knitta will get into a turf war with him!