I got to see Plants vs. Zombies 2 running at E3, and the game looked essentially done. That's why this news is so surprising. PopCap has tweeted that the title has been delayed from its July 18 launch to "sometime later on this summer." Note that it will still premiere on iOS.
There could several reasons for this. Popcap is part of EA, so perhaps the title must go through extra quality reviews, or maybe July 18 conflicts with something else in EA's lineup. It's also possible that Popcap wants to leverage other additions to the Plants vs. Zombies empire (the company is working