Cutting back Solidago (Golden Rod)

Hi. We recently moved into a property and inherited a pond (yay!) and also what I believe to be Solidago. I'm happy with the amount of it that we have, so my question is, once it's finished flowering, do I cut it back straightaway and also, do I cut it at the base, please? I've tried looking online but can't find a definitive answer regarding *where* on the plant to cut it back. Many thanks.

0
Posts
East facing, top of a hill clay-loam, cultivated for centuries (7 years by me). Birmingham