I like making green roofs but one problem with them is that I nearly always build on extensions and garden buildings at the back of houses so no one but the home owner gets to see it. Bike sheds are usually at the front of the house so they are on show to the world.
This one I built in Dulwich, London is for a client I built a sedum roof for last year. I persuaded them that this one would look nicer with a wider range of plants. I put in a selection of sedums including Sempervivum for long term coverage and then added herbs: creeping thyme, chamomile and rosemary. Then I added some saxifraga and a selection of plants that are flowering now for cover.
I think you will agree it looks fantastic now. If you want one for your bike shed get in touch. firstname.lastname@example.org