Green Roof – a year-and-a-half later

The green roof at Denver Botanic Gardens opened in November 2007. Within a year and a half, this garden has established very well creating a green space where once was a regular cemented roof. Situated above our former gift shop (soon to become a bistro), this one-of-a-kind green roof features native and drought tolerant plants that thrive well in our semi-arid climate with limited water.

A variety of plants were selected in creating this roof to test which plants will perform well as green roof plants in our region.  Departing from the regular norm of using Sedums as green roof plant materials, this roof is living proof of how, with experimentation, we can create a green roof utilizing a diverse plant palette. Designed and created by our resident green roof expert, Senior Horticulturist Mark Fusco, Denver Botanic Gardens is a pioneer in green roof research for our region.

The green roof was initially established using about 60 different plant species. Approximately 1,000 plants were planted and after the first winter the survival rate was quite high – 90%. Now, after surviving a second winter, the garden couldn’t look any better. This past week, the garden was splashed in shades of yellow, pink, red, blue and white. Plants blooming currently include three different cultivars of Delosperma, the bright red flowers of Echinocereus triglochidatus cactus, the bright yellow flowers of Eriogonum umbellatum, Euphorbia polychroma and Physaria bellii, pink and white Phlox and blue Veronica liwanensis. The Opuntias are in bud and should be blooming soon.

As this garden becomes well established in another couple of years, we will reduce and maybe even completely stop irrigating this garden.  Plans are underway to establish green roof trials at our Chatfield research gardens. The new Mordecai Children’s Garden, anticipated to be completed in summer 2010, will feature an extensive green roof, which will be situated above the new parking garage.