In 2008, approximately 1,800 native plants were planted on the 800 square foot Green Roof on the Gathering Place, located within the Lewis and Clark Native Plant Garden. The rooftop planting medium, known as "Utelite", is a mudstone material mined in Utah, then crushed and fired in a kiln before being mixed with a small amount of organic matter.
Native plants that would survive under hot rooftop conditions with low water and maintenance requirements were selected. The majority were also originally discovered during the Lewis and Clark Corps of Discovery Expedition (they are indicated by an *).
The following species were planted:
• Indian ricegrass (Achnatherum hymenoides)
• *Wooly sunflower (Eriophyllum lanatum)
• *Praire smoke (Geum triflorum) *Needle and thread grass (Hesperostipa comata)
• *Prairie junegrass (Koeleria macrantha)
• *Sandberg bluegrass (Poa secunda)
• *Spearleaf stonecrop (Sedum lanceolatum)
• Oregon stonecrop (Sedum oreganum)
• Broadleaf stonecrop (Sedum spathifolium)
• *Wormleaf stonecrop (Sedum stenopetalum)
• Sand dropseed (Sporobolus cryptandrus)
Benefits of Installing a Green Roof:
• Decrease the “Urban Heat Island” effect associated with the trapping of heat by black
rooftops and pavement.
• Provide habitat for birds and insects.
• Reduce the amount of storm water run-off.
• Provide excellent insulation, reducing heating and air-conditioning costs.
• Reduce indoor noise pollution from outdoor sources.
• Increase roof life expectancy.
• Filter pollutants and CO2 out of the air.
• Filter pollutants and heavy metals out of rainwater.