It didn't take any strength at all just a push sideways and the root was
out. I'm assuming the roots didn't get established much.

==>>> you are correct ... it was probably a poor specimen when you got it ...

return it for refund if you can ...

your success with the others tells me.. you basically did the process right ... planting.. watering.. etc ...

so dont lose any sleep about it ... an 80% success rate in anything endeavor is usually a happy time ..

ken

ps x 2:

a... thats not a very big root mass for that huge tree .. and it shows no indication of any root growth since planting ... from what i can tell on this pic ...

b. i hate to say it.. if not a root issue .. the culprit could be standing there staring at his best friend ... any hint of dog pee when you pulled it out???