Hard to say. Check the twigs, are they still supple? Is the bark green underneath when scratched? Are the twigs and branches shriveled? Those are all clues, but none are definitive in and of themselves.

There is a continuum from vigorous dynamic lush growth to death, and we don't know for sure how far towards the "dead as a doorknob" your tree is. You probably don't have a lot to lose at this point.

What I would do is REALLY flood the ground around it, let the hose run wide open for an hour maybe, to make sure the entire root zone is drenched, and then water it as needed to keep the root zone moist but not soaking. Then just watch and wait. The tree could be dead, could be alive but has significant die back, or it could just be somewhat dormant trying to wait out the drought and might come back rapidly.

Only time will tell.

do you see any green buds developing ...

my guess.. not knowing TX oaks.. is that it was. and is being drowned ...

i am not aware .. again.. in my experience in MI.. of any oak that needs that much water ... ever ... and the rain didnt help ...

whats your soil type.. did any of the rain water drain away ...

do you see any viable buds forming.. i have had poorly planted trees.. totally denude themselves.. and releaf .. if ALL other things are perfect ...

did it leaf out after planting.. in other words.. was it dormant when you planted it????

if its an evergreen oak.. perhaps it was dead before you got it.. and just didnt brown out.. until the real heat of summer hit ????

ken

I don't know why you would think drowned- "consistent rain" does not IMO indicate that it was over watered or even watered adequately for that matter.
We all have seen it rain what felt like was a decent amount and then gone out to see how much and there are dry spots under every shrub and tree. Rain falling from the sky OR a hose does not equal penetration and wetting of the root ball.
Some root balls even seem to literally repel water.

If I wanted to try and save it I would soak it thoroughly, but with a slow drip not a blast, and let that slow drip go for a while, perhaps even overnight. Then water it deeply and well at least once a week and hope for the best. That's assuming you are willing to do that and wait a long while to know for sure.

Personally I think it is a goner and it would be far easier to replace it but they do surprise me sometimes so you never know.

I have a 14 gallon, slow drip irrigation bag; is that too much? Should I prune any of the dead branches off? Some of them snap very easily and others still have some "bend" in them.

I wouldn't waste my time pruning but your irrigation bag sure sounds useful. It's a shame you didn't think to use it a couple of months ago :(
Worth a try.

Yes, I agree, the irrigation bag will work. Keep filling it at least weekly, if not more often, you will need to judge based on your weather conditions.

I wouldn't prune anything at this point, just wait and see.

OK. Initially, I did not use it because we were getting rain and I didn't think of using since because I thought 14 gallons was too much water.

I know I keep doing something wrong, because this is the 3rd or 4th Red Oak I've tried planting. I lost the last one because of the severe drought we had last summer and I wasn't at home to water it :(

Next time try planting either earlier in the spring or (my favorite) in the fall.
Summer is just tough all around for plants and double especially newly transplanted plants.

unfortunately, my HOA requires me to have 2 (live) trees in my front yard and I'm trying to get the landscaping looking a lot nicer for curb appeal because I'm selling my house later this year.

So, I'm stuck having to plant in the summer

IMHO, it's dead. What's more planting anything in the summer heat will almost end up the same way. Tree planting requires diligence, busy or not. If that means you hire someone that actually knows what their doing to take care of it, then that is what you have to do if you want the tree. That's the biology, and biology is not optional, nor accepts excuses.

Arktrees

Ah, this is where the investment in a programmable water timer and a little drip system would really pay off.