"Purple ice" dahlia (Ντάλια)

Dahlias are perennial plants, with mostly tuberous roots. While some have herbaceous stems, others have stems which lignify in the absence of secondary tissue and resprout following winter dormancy, allowing further seasons of growth. As a member of the Asteraceae the flower head is actually a composite (hence the older name Compositae) with both central disc florets and surrounding ray florets.
The pictured Dahlia cultivar was spotted growing in a house garden, in Tzoumerka mpuntains, Epirus region, Greece.