How do you save petunias that have been over watered?

You may be able to save Petunia's that have been over watered. It dependshow badly they were over watered. If your Petunia's have very wilted leaves that just hang, or the main stem causes the whole plant to sag downward or sideways then the stem is over full with water, like they would look if they needed water, then you won't be able to save them. This wilted look even though it was from over watering means that each cell that makes up those leaves has so much water in them they actually have drowned in it and the cells actually explode if they are given too much water. If your Petunia's do not show these symptoms then completely let your Petunia's dry out for about 4 days. If you expect rain and they're planted in the ground they may die this time it rains. Otherwise pick up the planter the Petunia's are in and move them out of where rain will fall on them.