Solidago species aka Golden Rod - but I can't tell you which one.

Thanks floral_uk. I wouldn't have guessed a solidago. I now see that it grows not only from seeds but rhizomes. No wonder it keeps coming back in all the same spots.

Could I please have that :)??!

I like it in my garden and pull where I don't want it. Mine grows too tall and flops so this year I cut it back in the summer. It bloomed shorter and looks great!