This name is a synonym of Symphyotrichum novi-belgii .
The record derives from TICA
(data supplied on )
which reports it as a synonym (record DDAA9500-8A93-4D3C-9937-265A698B9942
).
This name record (from TICA) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Aster tardiflorus in version 1 of The Plant List.