I was playing Zyra on live earlier, and I'd really like to give my opinion on her Q. I was pushed up to tower in the bot lane, and I was having a lot of trouble being able to do anything about them just pushing up on us. I really think her Q range needs to be increased for when you're in that small space and need to cast it out in front of you. Like, I've recommended this change once already, but I'm pretty sure there was no discussion on it. It's so difficult to hit as a poking tool when you're in that kind of position because once you get in range they begin to back off. There's an animation cast delay of like 0.25 seconds too which also makes it hard.
I'd challenge you to look at this, especially in the scenario I described. From a point of being behind and pushed up, Zyra's Q to me is useless, unless you want to make a plant that doesn't do anything except hit whatever is closest to it (a minion).
I just found an image of her old Q's range. There is a difference for sure. http://i.imgur.com/cc8t2wV.jpg