2010-10-15 Vienna XXII. district (Lobau Heisslände - heath, 155 m AMSL). Flower. German name: Weidenblatt-Herbstaster Leaf shape and flower size plus colour is intermediary between Symphyotrichum lanceolatum
(small leaves, small flowers which are usually white but may be lilac) and Symphyotrichum novi-belgii:
it is the hybrid Symphyotrichum × salignum.
Both species are introduced (and invasive) species, as is the hybrid; in Vienna, and especially in Lobau National Park, the hybrid however is much more common than either species.