lol - Day of the Triffids.
I was but a wee bairn when that was on the box.
Scared the hell outta me as I remember it.
But being a BBC sci-fi production of the early 80s, it's probably all shaky sets and rubbery monsters if you watched it now.
~
Whenever I see a heavy plant crossing road sign nowadays, I think of a Triffid crossing point.