Their modular hydroponic system -- where plants sit in a soil-free set up with nutrients delivered through irrigation channels -- can be retrofitted to just about any wall.

CNN: Green walls create new urban jungles

Then she set about designing a new model that could function as a hydroponic support system for the roses, able to withstand everything from wilting heat to high winds.

WSJ: The Kentucky Derby's Rose Queen

There are various systems for DIY constructions with most requiring a compost-based system, he says, but homemade hydroponic systems can be made using plastic bottles.

CNN: Green walls create new urban jungles