Conyza canadensis Canadian Fleabane DD I
This North American introduction was an occasional find on waste ground twenty years ago and now it is one of our commonest late summer weeds. It is found in public flower beds, shrubberies, waste places and building sites and is definitely on the increase. Stace says this is rarer in the North - perhaps he means Scotland because the North west of England is covered in it.
This plant has successfully invaded and conquered England but the Scots, Irish and Welsh have proved more resistant. It is uncommon in Scotland and Ireland.