The benefits of vegetated rooftops are pretty promising, and the City of Austin is considering funding a study to find out just how promising they can be.

"They're good at cooling, they're good at cleaning water, they're good at holding back storm water," researcher Mark Simmons said.

Simmons has been researching green roofs at the Lady Bird Johnson Wild Flower Center for the last four years. He is testing 18 green roofs, using the same plants in each, to compare water collection and see how things like the manufacturer of the green roof, the material used and native plants affect runoff.

Simmons is also treading in largely-unchartered territory.

"Globally, there is so little research done in warm weather systems. We've attracted a lot of attention from around the world just because we're looking at green roofs in hot climates," Simmons said.

Even though a few city buildings around town, including City Hall, already adorn rooftop gardens, this is the first time green roofs are being studied in a climate like that of Central Texas.

"Austin periodically has very heavy rainfall and you get a lot of flash flooding and other problems from rainfall coming off quickly off of impervious surfaces, like roofs and parking lots and roads," Matt Hollon, with Austin Watershed Protection, said.

At the June 24 Austin City Council meeting, city leaders will consider an agreement between the University of Texas and the Lady Bird Johnson Wildflower Center to pursue more research. If the city decides to foot part of the bill, it could end up costing as much as $10,000.

"As the city becomes larger and more dense and more intensive, are there ways that we can maintain our quality of life and have a lot of the environmental and social and cultural benefits that you would otherwise lose if we pave over these areas," Hollon said.

If these roofs can deliver the same results in Central Texas as in other parts of the world, the city might start encouraging more around town.