This is a side effect of having TJ's "Perfect Plants" in at one time and then taking it out. I once had that mod and when I decided it was way too cheaty I took it out. But every lot I visited after taking it out looked ragged but could not be trimmed.
Ah, that's probably what happened -- I removed Perfect Plants along with all my other hacks when I installed AL, and forgot to put it back in when it was cleared for AL. Only just noticed the borked bushes now, for some reason.
I agree with Zaz, though -- it's back in and it's staying in.