LiveRoof Celebrates Grasses

I spoke with Charissa Wagner, owner of Intermountain Roofscape Supply, a thriving LiveRoof green roof company for the past 13 years located in Whitehall, Montana. Intermountain has produced over 200 green roofs using the LiveRoof hybrid modular system, and according to Charissa, “We love what we do.” “We enjoy cultivating a product and having the satisfaction of knowing that we are helping to restore the balance between green spaces and hard spaces. Vegetation on a building brings many aesthetic and environmental qualities to a building that no other building product can bring. Growing grasses for green roofs is a very important practice, and could be said to be one of the most important practices when planting green roofs. When we plant grass on a green roof, we are trying to mimic prairies and meadows and restore lost habitat. Many of the meadows today have been covered up with buildings therefore many of our ecosystems have been disrupted or destroyed. When we plant our meadow roofs we use native grasses, wildflowers, and forbs to try to create a habitat similar to many of these ecosystems. The green roofs that we create, host many birds, insects, and bees that are beneficial and play an important part in our biosphere.”

Growing grass roof tops is uniquely different than growing grass at grade. In a natural prairie setting, you find grasses in a higher organic soil medium which is different from what is allowed in a green roof situation. There are some specific questions to ask and answer when growing grass roofs. The first question is “should you use short-rooted or deep-rooted grasses?” Charissa has learned over the past 13 years as a LiveRoof grower, that short-rooted grasses are better suited for roof tops than deep-rooted grasses. The next question involves the “number of grass species to include?” She grows most roofs with 5-6 different species with varying heights making sure to use grasses with an upright growing habit. Charissa then asks, “do you want species that smoother each other?” She does not use species that smoother each other or are overly aggressive as this would take away from the diverse beauty of the roof that many grass species create. Finally, “is there any additional focus when planning the grass roof?” Charissa tries to create unique habitats for animals and insects on each roof adding to the biodiversity of the roof.

Typical grass roof

Should we mow a grass roof? “Native Grass roofs do need to be mowed yearly, fertilized yearly, and watered weekly during the growing season in order to keep them green. In the absence of irrigation in the summertime, the native roof will go dormant, turn brown and can be a fire hazard, so keeping them lush and green is crucial until the summer is over, and fire season has ended.” Charissa Wagner