We are hopeful, here, about green transportation breakthroughs, setting our cynicism aside for any planet-pleasing press release. But — perhaps because we are suffering from a particularly nasty pollen allergy at the moment — we must look askance at this, the Moovel Lab’s “Green Skin” project.

The vehicle before you is a Smart Fortwo, carpeted with five square metres of God’s own clearcoat, plants. The team chose a blanket of frost-hardy, drought-resistant sedum plants, similar to the species Ford used for the Living Roof on its Dearborn Truck Plant in the US. Moovel claims that this will improve the environmental performance of cars, and that they’ll be on the road during a four-week pilot program in the Germany city of Stuttgart this month.

The team chose a blanket of frost-hardy, drought-resistant sedum plants, similar to the species Ford used for the Living Roof on its Dearborn Truck Plant in the US.

The company estimates that the green exterior can remove seven kilograms of CO2 from the air each year, while noting that a mature tree can filter 2.6 tonnes in that time. We suspect that may be offset yet again by aerodynamic inefficiencies introduced by those grassy planes, as well as the weight of the sod itself. Still, on an electric vehicle — ignoring things like manufacturing and assuming solar and wind power sources — the car might actually have a negative carbon footprint. But then, so would giving away a nice philodendron with every electric-car purchase.

The Moovel Lab is a part of Moovel, a subsidiary of auto-megacorp Daimler and parent company of Car2Go, a car sharing company with fleets made up of Smart Fortwos, cars that happen to made by Daimler subsidiary Mercedes-Benz. Circle of life, and all that. And we’d also note that the Fortwo is a popular canvas for artists at Art Basel and other places, and have been painted over only slightly less often than white plastic cows.

But (we sigh, taking another hit on our inhaler), maybe there’s something here. Auto engineers are looking to biomimicry for green solutions (as in as Ford’s collaboration with a gecko) and young inventor Param Jaggi has created an exhaust pipe add-on filled with algae that eats carbon as you drive. And we will embrace any swatch of living, breathing green, especially in the asphalted heat islands of cities. Maybe, if we want to grow the market for green transportation, we should seriously look into growing the cars themselves.

Or maybe someone’s been smoking some of that grass.

If you would like to comment on this or anything else you have seen on BBC Autos, head over to our Facebook page or message us on Twitter.