The Flower garden is a recreational room added in the Going Green DLC that prisoners use to grow and take care of plants in order to satisfy Recreational needs. Inmates do not require to be assigned to a program or safety training in order to work here.
A Shed placed in a Flower Garden, contains several contraband that can be used as weapons. For that reason, security measures should be put in place to avoid dangerous contraband from being moved out of the garden.
Prisoners can attend the Flower Therapy program which helps them to stay calm and relaxed by giving them something to care and look after. The program is Lead by a Gardener in the Flower Garden. Session lasts 2 hours and have 20 slots. Program must be started in Reports -> Programs tab.