Biofiltration is becoming an increasingly popular way to treat stormwater for stringent regulatory requirements in small footprints at affordable costs. This presentation will describe numerous ways to creatively retrofit existing drainage systems to incorporate biofiltration in a manner that best suits project drivers and budgets. The presentation will discuss lessons learned from the installation of over 20 systems on alternative medias, plant types and placement, physical configurations, multi-stage systems, manual and automated operational controls, and O&M triggers/considerations.