Redbuds are forest trees...they only occur out farther west than NE Oklahoma, down in dells and dips (out of wind and where more water collects) and I believe the range only extends to about the edge of Oklahoma/Texas anyway...so Oklahoma is the driest it can tolerate.
All you can do is see what comes in spring...they're pretty tough too..but ?

Redbuds don't need a lot of water. There is a native one growing in the middle of my greenhouse that has had no water since I pulled all the plants out last May. It not only hasn't wilted, it has grown. I would wait until next spring and see what happens. I think you are right in your analysis of what went wrong with it this year.

I've seen them (when I lived in Chelsea), turn crispy in a couple of summers (with no additional water...couldn't reach it)..but it survived...did lose some limbs though.

I lived in an area with high water tables...so it was basically flooded till May or June, with the ground weeping water...and it survived that.

There's always hope, and you really have nothing to lose by watching and waiting and seeing what it does in the spring.

I am so far south in OK that Texas sits to my west, south and east, and we have dozens and dozens of native redbuds growing as understory trees in our 10+ acres of woodland. The ones that do the best are the ones that are growing in dappled shade, or on the eastern or northern edge of the woodland where they have little exposure to sunlight in the mid-day or afternoon. The ones that don't do well are the ones foolish enough to sprout on the southern edge of the woodland, right where the woodland meets the grassland. They don't necessarily die, but they struggle with the full-day sun in July and August of every year.

One ridiculously silly redbud sprouted in the worst possible clay in full sun in a location several hundred feet from any water source about 10 years ago. We assumed a bird planted it there. That little tree has finally attained a height of 8'. Its foliage yellows, browns and drops every summer. I always think that "this time" it has had all it can stand and it is going to die. Then, the following year, it leafs out and is just fine until mid-summer heat and drought arrive. I never would have put that tree there, and I don't water it or feed it. If it lives, it lives. If it dies, it dies. The fact that it has survived so long in such unsuitable conditions is an indication of how tough redbuds can be. However, if you're trying to grow an understory tree in full sun, you may be fighting a losing battle. It isn't that it necessarily will die, but more that it just will have periods of time when it is very unhappy---and it shows.

Both Chinese pistache and desert willow are very tough, strong survivors that can tolerate almost any conditions. Both of them are stronger and tougher than redbuds, so it doesn't surprise me that they are fine even though maybe it is not. That's exactly what I would expect. Desert willows, by the way, are deceptively named, being neither desert plants nor willows. They actually are closely related to trumpet creeper vines (a plant about which it is commonly said "they won't die and you can't kill them").

I love redbud trees. They are so gorgeous for that couple of weeks in spring when they are in bloom, but I've never planted one on purpose. I'll never buy one and plant it on purpose. I just think that there are many higher-quality trees that deserve a spot in a landscape and that look better year-round than the redbuds do. I prefer to give prime landscape space to plants that are not going to struggle so much in the heat of the summer. Since we built our house on higher ground in full sun with dense, compacted red clay soil, the area around our house is not a suitable location for redbuds, which do fine here on lower ground, with sandy soil, in the woodland along the creekbeds. That is where they belong.

So, my suggestion is to evaluate your landscape and ask yourself if the redbud will be happy there long-term. Will it get the afternoon shade it prefers? Or, at least will it have shade from other trees in the middle of the day? Is it planted in a place that makes sense for it? So often, we choose plants we like and put them where we want them instead of putting them where they need to be. Is this redbud growing in a place where it will thrive equally well in hot, dry years and in cooler wetter years? If it isn't, you have to decide if it is reasonable to expect it to thrive where it is growing or if maybe it needs to be transplanted to a location that would be better for it. Your tree's struggles this year may be totally related to the heavy irrigation required to get the new sod to grow. Or, it may be a sign the tree just isn't in the best location that gives it what it needs.

Good luck with your tree, and I hope it rebounds next year.

I needed a small tree for the NE corner of my yard, which was originally shaded by a neighbor's large tree--which was subsequently taken down because it was too close to an electric line. Not a thing I could do about that. My tree is on the east side of my 2 story house, so it does get a bit of protection in late afternoon/early evening from my house shadow. That said, it is now basically in full sun, but has done well the previous summers even the hideous 2011-2012 cauldrons. I have not had to baby it along, but I agree that the growing conditions could be more optimal. It's way to big for transplanting, not to mention the $$$, so that's out of the question. Also I have nowhere else to put it!

Thank you, everyone, for your help and words of wisdom. I will wait till spring, hope for a mild winter, and keep my fingers crossed. If it doesn't come back in the spring, out it'll go, and I'll probably choose a more full-sun small tree, with hard wood, that is also very hardy, disease resistant, easy to grow and doesn't have seeds or things that drop off it it (other than leaves in winter). Lol--I don't want much, do I?

This is the redbud in my gh today. No water since April, temps that have gone to 120F. This is a native of course. I didn't plant it in here. I think it was there before the house was built. We dug out the asparagus that was there, missed the tree.

Those leaves are actually beautiful. You've got to let it do its thing now--the little engine that could. Respect.