As you walk round the high walks and the Podium surrounding the blocks of the Barbican estate, you will see many concrete containers containing plants and flowers. These are maintained by the City Corporation (as opposed to the log-cabin style boxes which are maintained by residents).
The City’s gardeners replant their boxes twice a year to provide Winter and Summer flowers. But this doesn’t really work in the Winter when the containers sometimes look like opened coffins from a horror movie. It would be much better if the City would plant them with small trees and bushes, with flowers around the bases, so at least they would look lived-in during the hard months. (My own window boxes look like coffins all year round, so perhaps I shouldn’t offer advice.)