More and more commercial developers are investing in sustainable urban oases to give their projects an edge.

In Austin, a collective focus on green building is giving local landscape architects the opportunity to pepper today's commercial projects with the latest in sustainability and outdoor design, whether it be a rooftop garden or stylish outdoor workspace.

Sustainable landscaping -- from native plants to energy-saving water irrigation systems -- is becoming more commonplace in Central Texas, says Daniel Woodroffe, principal in landscape architecture firm TBG Partners.

"It's definitely become the norm. Landscape architecture is a powerful cure for new and existing properties," Woodroffe says, referring to the functionality and aesthetics of landscaping.

In the last few years, the firm has been tapped to create rooftop gardens for the local Ronald McDonald House, Dell Children's Medical Center and The Austonian -- arguably the most high-profile sustainable landscaping project in Austin.

When the Austonian's residential tower is finished, the 17,000-square-foot rooftop garden will be the largest in Texas, boasting a 75-foot pool with fountains, a dog park, herb garden, fireplace and reflecting pool.

The rooftop garden is also a sustainable centerpiece, with native plants and an architectural-looking water management system that will enable the harvesting of rainwater. The garden will also give off a "heat island effect," meaning it will act as an antidote to the high temperatures created by downtown's hard services, Woodroffe says.

Woodroffe declined to say how much the Austonian project cost.

The price tag for stylish landscape architecture can be steep, many landscaping executives and their customers say, but the investment can pay off in increased property values and increased usable space. Also, landscape architects are quick to say they can devise creative solutions for almost any budget.

Dylan Robertson, principal of D-Crain, says that, despite the economic slowdown, his residential and commercial clients continue to see the revenue-generating potential in outdoor spaces. Robertson has designed outdoor environments for Hotel San Jose and Uchi, among others.

"Over the last couple of years in the commercial arena, we have seen landscaping become one of their highest priorities because it creates a real life usable space; it is usable real estate," he says.

While outdoor space has been historically underutilized in commercial settings, there has been a recent movement toward creating outdoor living spaces for employees, Robertson says.

For instance, D-Crain is working on creating such a space for a business park in Round Rock.

"This will not just be a place where employees go for a cigarette or lunch," Robertson says. "They will be truly able to work all afternoon, and not just have an office party outside, but a seminar."