The Keen of Hamar is Unst's less well known nature reserve along with the more famous Hermaness. It is run as a nature reserve by Scottish Natural Heritage who can be contacted on Unst (01957) 711278 or at their Shetland office in Lerwick (01595) 693345.
The Keen never fails to amaze visitors. Even in the height of summer it appears to be a bare, brown, barren hillside - yet close up it is covered with an array of tiny yet beautiful and fascinating plants.
The most unusual is the Shetland Mouse-ear, also called Edmondston's Chickweed. This tiny plant produces relatively huge white flowers about 1.5 cm in diameter, with the plants growing out of the rock debris itself. The plant is only found on Unst and nowhere else in the world. One of its names commemorates its discoverer, Thomas Edmondston of Buness on Unst who discovered the plant as a teenager last century. He was made professor of botany at Glasgow University before he was 20 and died in a freak accident in Peru a year later.
Several species found on the Keen are normally only found at high altitude in the rest of Britain. These include such plants as Norwegian Sandwort (one of very few plants in Britain given special protection by law), Northern Rock-cress, Moss Campion and Alpine Meadow-rue.
The lowland, serpentine debris habitat is unique in Britain, although there are similar sites in Sweden. Serpentine is an unusual rock with a high level of certain heavy metals and low levels of nutrients. In Britain it is only found in Cornwall, the Inner Hebrides, Aberdeenshire, Fetlar and Unst. The unusual rock and poor soil undoubtedly contributes to the Keen's uniqueness, a large part of Unst is on serpentine rock but it does not have the same unusual plants. Recent theories suggest that drought stress on the Keen may be an important factor!