July is a great time to visit an ecoroof in Portland. Many of the most common sedum varieties are blooming now, drawing in an assortment of pollinators in addition to the honey bee.
Ecoroofs across town are capped with the white flowers of sedum album and hispanicum, and the yellows of Sedum rupestre, oreganum, kamschaticum and sexangulare. Delospermas, also known as ice plants, are beginning to flash magenta and will continue to do so for a few months. But gone are the spring flowers of Sedum divergens, acre and spathulifolium, leaving only stems and seeds to help shade their foliage as the dry season continues.
Lupines are winding down but wildflowers like Gilia, Tarweed and Geum are blooming now. Weedy volunteers like epilobiums and many members of the aster family are flowering as well, seeds blowing in the wind, and urban pollinators and birds are finding uses for them. Fescues, Deschampsias and other grasses are also producing seed now. Yet to step into the spotlight are the deep pinks of the many varieties of Sedum spurium, and the towering (relatively) telephium and spectabile cultivars such as ‘Autumn Joy’. They’re putting on ounces in quiet anticipation of fall. It’s a great time to study up on just what pollinators are using these urban habitats. Contact BES if you’d like to find out more, or see some ecoroofs in person.
While that’s all going on, ecoroofs are performing some of their most important stormwater management services. Portland ecoroofs have shown the most stormwater retention during our infrequent summer rainstorms due to the higher evapotranspiration rates and unsaturated soils. This is important because regulations for water quality and combined sewer overflows are more stringent in summer, when there’s typically more time for pollutants to accumulate between less frequent rainfall.