Male Common Blue. This Blue is the most widespread species in Wales often being seen on coastal walks. The males have a bluish purple upperside. To encourage Blues to the garden, it is best to encourage a short-turfed grassland area which is cut in the winter or spring. After a while, the larval food plant, Bird's foot trefoil, should colonise on its own from neighbouring grass verges. Blues nectar on smaller flowers such as this corn marigold above but also use fleabane, thyme and marjoram.