Question
I understand  that we must not over water container petunias, but our weather (excess rain) this summer has certainly not helped. Can I do anything to bring what were beautiful plants back?

Answer
First, the pots have to be perfectly draining.  If they're not, change that.  Petunia roots can't stand the water or the lack of Oxygen.

Next, let the roots dry out.  Remove them from the soil they're in and set them out someplace dry.  If they need it, put them on paper towels.  Time is of the essence.

Pinch the Petunias -- cut them back an inch (or 2 if needed). This time of year, Petunias that have been growing all Summer need a second wind anyway.  Pinching/pruning/whatever you want to call it will give them that breath of fresh air, stimulating hormones to grow leaves and more flowers.

When the roots are aired out sufficiently (not DRIED but aired out, i.e. more Oxygen is able to circulate around them and the soil is no longer soggy), re-plant them and PROTECT them from rain.  Cover them at night with newspapers or towels.

If these were worth it, I'd say give them a few doses of triage-level "Messenger", a fairly expensive product that is a kind of CPR for plants.  But they are so cheap, and the Summer is 2/3rds over (however Petunias do bloom through November in this area), it might not be worth it.  The sooner you get the Messenger in the I.V., the faster the recovery.  They can save you a good 2 weeks of Petunia pain and suffering.

Who knew this much precipitation was on the menu for the Summer of '09?

Next time, remember that old gardener's saying: Into every life some rain must fall.

THE LONG ISLAND GARDENER