Classic images of recent transplants running short of water in the rootball area.

And depending on the cultivars involved, the spacing looks too close for healthy growth.

btw, 6 hours of direct sunlight for a bigleaf hydrangea is probably a bit more than they are happy with, especially if that sun comes later in the day. All day dappled or filtered shade or morning sun/afternoon shade is the preferred siting.

And where are you located in zone 6 that hydrangeas are already blooming? Or are these greenhouse or florist's hydrangeas that have recently been planted, in which case the appearance is entirely expected as these need a period of time to harden off or become acclimated to the outdoors before planting.

I am in Eastern Oregon, Milton Freewater to be exact- all my hyrdangeas have been nursery raised. I bought my healthier hydrangea in late March and hardened it for a month before letting it out 24 hours a day... as you can see it is VERY healthy and has grown more since I have planted it. My other hydrangeas hardened for 2 weeks before full 24 hour exposure and even before transplanting... they did EXCELLENT outside. I even put my hydrangeas in their transplanted location before actually putting them into the ground.
The other thing I didn't mention- we have had extremely late spring rain for a change and more cloud coverage than I would like at this moment. I dug around a bit ago and the ground is very well saturated. We are going through a very cold front right now from Alaska and I am really worried they wont make it through the night...
The plants have three feet between them in placement, I thought that would allow plenty of growth room for the root systems...

It was said "And ... the spacing looks too close for healthy growth."

Yes, that too. But that's not the current problem.

OP said "the ground is very well saturated" -- that's nice. But the rootballs are dry.

Water won't go sideways from wet soil into dry rootball.
Please drizzle water directly onto the rootball of each recent transplant.

Did you harden them off? If they weren't outside for a period prior to planting, they may be sun scalded.

sunscald looks very different than drought-stressed leaves.

yes I did harden them off... I actually moved them to the front of my house on Monday where they will have more sun. I made sure to check two times a day for moisture on the root ball.. they are doing better- however we have had three days of constant rain and very limited sun exposure- will this put my newly moved hydrangeas in shock-killing them?

I don't think it is either too much sun or not enuf water - I think what you are looking at is cold damage.

Open flowers on any type of bigleaf hydrangea now in the PNW is an indication that the plants are either greenhouse grown or from out of state. And the OP indicates these are NOT greenhouse grown plants. At my nursery, we get a lot of plants from California that are well ahead of our local bloom season - hydrangeas here do not start blooming until the end of June or early July. If they came from out of state, they may have not had sufficient time to become acclimated to our colder climate. And our PNW spring weather has been colder and wetter than normal - a relatively mild frost about a week and half ago nipped all the CA hydrangeas we had on the nursery floor and they ALL have an appearance very similar to the OP's - purplish foliage and crispy flowers and leaves. And while it may be warmer daytime in the WW-Milton-Freewater than it is here in western WA, I'd be willing to bet nighttime temps are still pretty chilly.

If it is cold damage, they will come back from that rather easily, although you may need to trim off the damaged portions.