The Morton Arboretum's green roof, on a portion of the Visitor Center's rooftop, demonstrates a commitment to improving energy efficiency, reducing the carbon footprint, and beautifying the world. The green roof is not accessible for public viewing but is utilized for participants in education and horticulture programs.
Why plant a roof?
- Reduce heating and cooling needs
- Cut down on heat radiation
- Extend the life of the roof itself
- Reduce storm water runoff
High tech, low impact
Special engineering makes it all work. A six-inch soil substrate supplies the needed plant growing material, while layers of mineral compounds and foam provide drainage and filtering. Roof drains and a rubber membrane prevent water from seeping into the building, and a modified weight system keeps the building structurally sound.
Survival on the roof
It takes carefully chosen plants to make a green roof work.
Stonecrops, also known by their botanical names, sedum and hylotephium, are perennial succulents with thick, water-storing leaves and ground-hugging growth habits. The 400 or so species of stonecrops come in diverse colors and often produce vivid flowers. Their real attraction, however, is their carefree nature and tolerance for drought. Among the stonecrop's on the Arboretum's green roof are:
- Autumn Fire Showy Stonecrop (Hylotelephim spectabile 'Autumn Fire')
- Purple Emperor Stonecrop (Sedum 'Purple Emperor')
- Mossy Stonecrop (Sedum acre)
- Two-Row Stonecrop (Sedum spurium)
A blooming cactus that grows in Chicago? Yes! Opuntia humifusa is a low-growing hardy perennial that can tolerate northern Illinois winters. Recognize it by its low, flattened pads and showy, satin-yellow flowers in late spring.
The leaves on Stachys byzantina are covered with silky hairs that make the foliage appear gray. The soft woolly foliage provides appealing texture, while their preference for sunny, dry locations makes them relatively low maintenance.