Another Day of the Triffids!
Walking plants that spit poison combined with a global catastrophe that leaves most of Earth's population blind. John Wyndham wrote the book in the 1950s. Although most people remember it more as a technicolor movie with Howard Keel. Do yourself a favor -- read the book. Do yourself another favor -- read all of Wyndham's books.
Anyway, there's a new BBC version of Day of the Triffids.
Check some out at SF Signal.