Day of the Triffids
In a way, this novel struck me as being a zombie story as much as one of vegetables run amok. Same idea - slow moving, easy to avoid if there are few and you can see them, but gradually they overcome the survivors of whatever giant disaster by virtue of sheer numbers and blind (ahem) aggression.
And, okay, so it's not really a dystopia, it's post-apocalyptic, but it's close enough and I wanted to read it.
The last book I read before this was, of course, War With the Newts, and I found there to be many similarities. Man finds resource that he does not consider overly dangerous or sentient, spreads around world, is warned but ignores it, is later punished for his hubris. Newts delved much more deeply into the worldwide events and reactions, with Triffids being more of an adventure story, but as companion pieces they work.
As I mentioned before, I'm pretty sure this is one of Stephen King's favorite books. Not that I've ever seen him mention it, I just feel like he's adapted large chunks of it and used it to flavor most of his best writing. So, I just now looked up "Stephen King" Wyndham on the ol' google, and what's the first result? 'The famous American writer Stephen King has called Wyndham "perhaps the best writer of science fiction that England has ever produced".' Yep, you can tell.
final thoughts: I've already loaned my copy out and suggested it to a few different people. Easily one of the top 5 novels I've read this year.