Plant in a solid concrete or similar planter, or preferably someone else's garden.
Do those plastic wall things not work?
@ColinTheBald started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Plant in a solid concrete or similar planter, or preferably someone else's garden.