You may already associate the 2010 Toyota Prius with flowers, courtesy of its "Harmony Between Man, Nature, and Machine" ad campaign, complete with human flowers in the "Harmony" TV spot.

Now Toyota has taken flower power one step further, creating two new species specifically to help reduce the environmental impact of Toyota Prius manufacturing at its Tsutsumi plant in Japan.

Absorbing NOx, emitting water vapor

One is derived from the cherry sage plant, with leaves that absorb nitrogen oxides. The other, a derivative of the well-known gardenia, releases water vapor into the air, which reduces the temperature around the factory, cutting the need for air conditioning inside the building.

The Tsutsumi plant at Toyota City, where the Prius is built, includes rooftop solar panels to generate electricity, and exterior paint to absorb both nitrous oxides and sulfur oxides from the air. Inside, motion-sensing switches turn off lights in unoccupied bathrooms, and reflective light tubes channel daylight into rooms to replace electric lights.

Toyota flower

Toyota flower

At 82 degrees, no neckties

Offices at the plant are cooled only to 82 degrees in the summer and, unusually for Japan, white-collar workers may dispense with neckties and wear short-sleeve shirts for comfort.

Even the grass outside the plant--interspersed with more rows of photovoltaic solar cells--is a slow-growing species that only needs to be mowed once a year, cutting energy consumption. And last year, Toyota planted 5,000 trees to offset the factory's carbon dioxide (CO2) emissions.

Cutting carbon, criticism continues

Those features, the new flower species, and other efforts are part of a broad-ranging plan by Toyota to reduce the environmental impact of manufacturing the Prius hybrid-electric vehicle.

A steady drumbeat of criticism has been aimed at the 50-mpg Prius, whose manufacturing creates more CO2 than that of other cars, offsetting its fuel efficiency.  Toyota says that the difference in CO2 is compensated for after a single year of operation.