The common rock-rose (Helianthemum nummularium) is a plant that favours calcareous soils and can be found from May through until September on dry, grassy or scrubby areas in Dorset on the chalk ridge to the north of the county and along the limestone coast of Purbeck and Portland.
Not a rose at all, it is a member of a very small family of plants, the cistaceae. There are just four members of this family and the others are more common in mainland Europe and are very rare here in Britain. The common rock-rose has five yellow petals with an orange centre that can be seen from June until September. It is, in fact, a dwarf creeping shrub and each plant produces a number of individual flowers over its summer season
Rock-rose is a favoured food plant for some butterflies, especially the brown argus, the green hairstreak and the silver-studded blue. It also, supposedly has healing properties and is used to calm individuals who have suffered extreme panic, terror or hysteria. It restores strength and courage.