Macrophylla (mop head/lace cap) should do well in these conditions (I had a big blue hydrangea near a downspout at our last house and it did very well, actually too well as I had to prune it back hard many times over the years but I gave away lots of rooted branches when I did prune it back). Oakleaf and paniculata types would not do well in this wet area though.

I heard that Astilbe do well in wet spots too but I gave up on those. Colocasia should do very well there if you get a lot of sun with a constant wet ground. Ferns and hostas are another possibility.

Have grown numerous paniculata types in sopping soil. They are native to areas with streams running right by their roots so they like it wet. Limelight does great with moist soil- will take a couple years to become well-established.

I've had Limelights do fine in soil that stays wet for long periods during the spring. The same conditions have killed Incrediballs.

No hydrangea will survive in either standing water or very wet clay. You didn't mention the type of soil you have but if it's heavy you could raise a grade a bit by adding mentioned organic matter mixed with some sand or grit. And aim for macrophyllas, these appreciate constant moisture at the roots as long as they're no suffocating in mud.

I know this is old, but what about arborescens ? We get big rains / hurricanes in fall and good spring showers too that leave some areas a little damp for a few days after.

One of the smaller Clethra or Itea might do better in this setting.