The alpine slopes of Kenya’s extinct volcanoes are the floral equivalent of Bordeaux. It’s there that the roses grow for the world’s weddings, funerals and Valentine’s Day bouquets. The higher the altitude, the larger your flower head, and roses raised in the shadow of Mount Kenya’s glaciers, or on the vast caldera of Mount Elgon, come in a dazzling spectrum of colours, petal shapes and scents.