In Plants vs Zombies 2, to get some stars you must plant less than a given number of plants.
In those levels, do Pea Pod upgrades that go onto existing Pea Pod count as extra plants?
The Encyclopedia seems to indicate this way – it explicitly refers to "multiple plantings" and "repeatedly planted in the same space". Also, I have experienced "losing" the star level when I had zero plants to plant left and I planted a Pea Pod upgrade.
However, I'd like an official answer based on some sort of PvZ documentation to confirm my observations and guesses.
Best Answer
Didn't you just answer your own question?
So yes, planting a Pea Pod anywhere(including existing ones) counts as planting an extra plant.
EDIT
From Pea Pod wiki: