The major part of Stora Karlsö is a flat limestone plateau, almost completely bared because of grazing sheep. The sheep were removed in 1887 and the plateau filled with grass, brush and trees, which led to the loss of some valuable flora. Then, after 108 years it was decided that the sheep should be brought back and parts of the island are once again filled with a multitude of flowers, depending on the season, e.g. intense blue veronicas, white daisies, yellow stonecrop, fragrant violet thyme and many, many more.
In late May or early June there are thousands and thousands of orchids – a sight to be seen! Special ”orchid tours” led by experienced guides are arranged from about 20 May to 5 June, depending on the weather.