admiral Buddleja butterfly eating flower nectar proboscis purple suck sucking summer Vanessa atalanta black England english flowers Great Britain hydrangea insect Lepidoptera natural nature petals red red admiral rest rhopalocera white wings Aster Buddleia butterflies Ceratostigma Cimicifuga Clethra Cotoneaster garden Hebe Helichrysum Hemp agrimony ivy marigold Michaelmas Daisy mint nettles Sedum verbena