Living Green Roofs

Prairie Grass Roof
Walking Mountain Nature Center
Avon, Colorado

It may not be readily apparent, but road warriors can have a green side.  Topside that is. The Ford Truck Plant in Dearborn, Michigan manufactures large scale, gas loving pick up trucks beneath a roof covered with live sedum plants.  Ford's green roof is a pasture of 10.4 solid acres of sedum which benefits both the environment and the economy.

Ford's green roof was one of the first large-scale commercial projects of its kind and has been benchmarked by an industry leaning towards greener practices. 

Not only industrial facilities can benefit from living roofs overhead.  Residential homes and even garden sheds have incorporated plants into construction design. The primary benefits of a green roof for the site owner are improved insulation against heating and cooling loss and rainwater run off absorption. 

Sedum Roof, Ann Arbor, Michigan

Sedum is the gold standard for green roofing due to the groundcover's ability to absorb rainwater.  The succulent fills in quickly, survives extreme cold and windy temperatures and doesn't require pruning or cutting back.  Prairie grass is sometimes used as an alternative, but in the wrong setting can dry out or overextend.  Visually, sedum generally appeals more to the eye.  Ideally, the roof should incorporate a more diverse collection of plants, but sedum can be a bit pushy.  

Low maintenance sedum sports a shallow root system, tolerates drought, resists disease, adapts easily to environmental challenges, and requires no supplemental nourishment.  Yet, any significant installation design should include an expert's opinion as the vegetation blanket's weight increases as the plants grow, multiply and absorb water.

There are thousands of varieties of the stonecrop species.  The most suitable are short and compact as tall species can suffer breakage.   If aesthetics are part of the equation, available sedum colors range in color from bright yellow, to green to burgundy red.

New York City offered tax abatements for developments sprouting living roofs. 

Grass roof
Avon, Colorado

Are plant based roofs truly beneficial?  There's no solid evidence either way.

One thing's for certain, sedum plants won't limit themselves to the roof.  The spreadability factor which makes stonecrop so attractive for roofs doesn't end at the gutter.

Expect sedum to reseed at ground level.

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