Black hairstreak forewings. The most conclusive way to distinguish the two is by the row of black spots accompanying the orange band which the white-letter hairstreak never has. They spend most of their lives in the canopy or in dense scrub, feeding on honeydew, and very rarely come down to ground level. Eggs are laid singly on young blackthorn "Prunus spinosa" growth and it is this stage which hibernates. Although blackthorn is the main foodplant, wild plum "Prunus domestica" and other "Prunus" spp are occasionally used. The caterpillar hatches the following spring, at the end of April, just before the buds open
Prunus subhirtella Prunus subhirtella Prunus subhirtella ("Prunus" × "subhirtella") or Prunus pendula sometimes also called winter-flowering cherry, spring cherry, Higan cherry, or rosebud cherry is a small deciduous flowering tree originating in Japan, but unknown in the wild. It is probably of hybrid origin between "Prunus incisa" and "Prunus spachiana". "Prunus subhirtella" bears white to pink flowers which may emerge intermittently from autumn through to spring, and small black fruit. Several garden forms are known. The variety 'Jugatsu-zakura' (incorrectly known as "Prunus" × "subhirtella" 'Autumnalis') is widely grown for its propensity to flower during mild winter weather. The flowers can be used