To Kill A Buddleia

I wrote recently about formative pruning of Buddleia, and I used the phrase “...there is practically nothing you can do to kill them!” I've had a couple of humorous messages from Patrons ( waves cheerfully “Hi, guys!” ) on this subject, and one plaintive plea asking if there is a way to kill off one that you absolutely don't want. Funnily enough, I do have an example: in one of “my” gardens, I am…