I need to plant some young trees in my backyard's clay soil (new construction). We are in College Station. I hear that I need to buy some product to put in the bottom of my tree holes to help with the PH for the clay soil. New homeowner, first time tree parent, learning as I go.

What product is this that improves PH and the success of trees?
What do I need to know about planting 15-gallon trees by myself?
And if you are local to CS - what's the best place to buy trees?

Thanks!

Go to producers coop ask them and buy it. Friend got some kit of stuff and a schedule when to apply what and his trees grew like rocket fast.

Why not just plant trees that work with soil you have so you don't have to artificially support a tree forever? Is that an option? I have oaks and mesquite in my yard. Solid rock and clay and they seem to survive on 4" of rain per year.

Use this https://texastreeplanting.tamu.edu/
Pick a recommended tree. Ask the folks you buy the trees from what they recommend. Maybe some kind of liquid root starter. I wouldn't try to alter the pH.

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Garden Success KAMU-FM radio

Amateur still learning since the 70s & black thumb in clay soil over shale layer report:
Chinese pistachio: wonderful survivor, grows fast, dies after 20 years but then
Live Oaks: planted nearby take over - but they do not like salty city water in droughts (like last summer) unless you know all the tricks
Cedar Elms: Survivor like the above, long-lived like oak, almost as fast as CP above

The others were volunteer Post Oaks, Hackberry, etc. that are NOT on the recommended list anywhere.
With irrigation, had 10yr luck with persimmon, fig ....

Neighbor had luck with 13-13-13 w/sulphur fertilizer.

All the above is tangent to & subservient to advice gleaned from pros @ Producers or Garden Success.

Certified Arborist here....
Generally, changing the pH of soil over the long term is a losing battle. There are products out there that will allow you to raise or lower the pH for a time. However, a given soil has a pH it "prefers" due to its overall makeup. I try my hardest to kindly steer my clients toward plants that work well for the area. We call it the right tree for the right place. Since pH is generally going to stay constant regardless of our efforts it is better to choose species that thrive in our area.
Be sure to plant your trees somewhat tall in clay soils. The deeper you go in clay soils the less available oxygen is. Oxygen is vital for root growth.
Tree Nerd Out.