Sigh - I don't hire help in the garden any more. One pulled up 90% of my
perennial ageratums.

I hear ya.

But when the puller in question is your partner/spouse, it isn't quite
that simple :-).

The current method seems to be a tag and/or stake next to every wanted
plant. We'll see how that works. Volunteers which we might want to
keep will be the real challenge.