madeyna thank you for your suggestions. I hope I am as lucky as you! My amazing limelight was about 8 feet tall and covered in the most gorgeous huge blooms. Now it is turning brown and drooped over to about 4 feet and very sad looking. Sigh, just about every plant in my yard is looking awful. I will keep up watering and hope it doesn't reflood the basement LOL

Salt is big killer of plants because it interrupts various process on the plants, the most obvious of which is dehydration. Instead of the roots absorbing water, salt in contact with the roots absorbs water from the roots. I would water more frequently to try and dilute it as madeyna recommended.

I do not know if these other ideas will work but, when cooking, people counteract the TASTE of salty foods in some ways that I do not know how practical they can be to you.

For example, potatoes absorb salt like sponges absorb water. Should you cut slices, carefully mix in them in the soil (so as not to disturb the roots much), water and then pick them up in a few days? and dispose them? I do not know; can't see myself doing that but I do not have the urgency that you have...

For example, I sometimes add lemon juice or vinegar to counter the salt. Is this just affecting the taste of the food? And leaves the salt always there? Does it change the salt into someting harder to absorb? I do not know. Will it work on plant roots/soil/etc? I do not know either.

You can also try to prevent moisture loss via the leaves by applying Wilt-pruf, an anti-transpirant. I would also cut the blooms and maybe some of the top growth so the small amount of water still going into the plants is not wasted in browning areas.

As long as the soil stays moist I wouldn't even water them much (the ground was probably waterlogged from the flooding anyhow). The plants might not fully recover until next Spring, and may drop leaves earlier in the fall.

Natural disasters usually aren't good for any plants, especially hydrangeas. They'll need time and probably some dieback to recover.

To move salt out of damage zone in upper soil would take leaching, a little different than just copiously watering and it doesn't sound to me like your landscape could handle that right now - or your basement :) And, I think it may be too late now that your plants have had a few days to take up the salt.

Leaching: more than irrigating, it is a deliberate flooding for several hours, with the intention of picking up salts or contaminates and moving them down lower in the soil out of reach of the plants roots.

Some of the damage you are seeing will be from the wind and spray, the foliage has been battered. It's unfortunate and I don't mean to make light of your distress, but these natural disasters sometimes happen and all we can do is go forward, clean up, replant if necessary. I agree it may be next Spring before you know the extent of loss and recovery and fully know what steps you will need to take.

I would make things look as clean as possible, water on your normal schedule, clean up any jagged breaks with sharp pruners to prevent secondary disease or insects from entering stems. While my advice is coming from the other side of the country out of harms way, we did have winds that were measured at 119 before the instruments failed one Dec, I lost a good portion of an expensive shrub border to a falling pine (on its way to landing on my house :))....gardens will recover given some time.

Another thank you to everyone for your input. I think the best I can do is go back to regular watering (yes, the ground is soaked) and pray the garden gods are good to me.

Irene brought down 2 80 foot oaks in my yard-one smashed 5 hydrangeas-nothing to do but clean up...sorry