A Splash Blue in the Shadow of St. Paul’s
by Dusty ~ March 21st, 2011. Filed under: Green Roof News, Nature Notes, wildflowers.We planted the Muscari bulbs on the green roof at Evershed’s three years ago. The bulbs were part of a scheme to increase the biodiversity potential of the basic sedum blanket green roof that lies in the eastern shadow of St. Paul’s.
Although they are not a native species they serve two purposes: aesthetics and biodiversity. Whilst the majority of the roof is slowly turning to moss as many sedum blankets do the muscari give a flash blue early in spring to delight the eye. We also know that early rising bees will use bulbs such as Muscari as a nectar source. This is important in early spring but this year particularly so as the cold grip of winter is lingering well in to late march and bees are very vulnerable to the cold. Bumblebees need instant high calorie food to sustain them and ensure they slip through the cold hands of the weather.
There are 9 clumps of Grape hyacinth on the roof planted into the small mounds we created to add diversity. On this mound the green stalks of Chives Allium schoenprasum can be seen readying themselves to flower later in May. I counted at least 10 species of herbs waiting for the sun and warmth of late and early summer, when they will play host to a range of invertebrates and bugs the simple sedum roof would not be able to do.

March 21st, 2011 at 1:34 pm
Great looking roof! My grape hyacinth are also popping up. My chives wintered over, and surprisingly, so did my parsley.
Thanks for mentioning the need to add herbs to a sedum roof. I was unaware of the benefits they provided.
March 21st, 2011 at 1:39 pm
Cheers William – I have been fitting a battle against the prescription of simple sedum blankets for years now. Even in DC there are a number of herbs and natives that can be installed on an extensive green roof 4in deep. I managed to do this on a small roof as part of the Folklife Festival in 2009. The roof now resides at the Enchanted Forest near Baltimore. Be great if someone could visit and let me know what is looking like. Oh and Ed Snodgrass helped me build it and supplied the plants.
April 14th, 2011 at 8:45 am
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