Baby trees

Baby trees

I just received ten baby trees from the Arbor Day Foundation. They're all *tiny*. Since I can't plant them tonight, I stuck them in the fridge, where the instructions say they should be okay for a few days. I have a potential problem: I live in an area with black clay. A lot of plants die because they can't get their roots through the soil. In order to give the trees a better chance of surviving until they're stronger, I thought of planting each one in its own planter. I have some deep planters (I'm not sure how deep, but they're a couple of feet high), or I could go buy some 5 or 10 gallon buckets if that would be better. My question is, would this work? And is there any chance the trees could hang out in 5 to 10 gallon buckets for the first few years of their lives without harming them? If it helps, I'm in zone 7 (NE Texas), and the trees are various types of flowering trees (dogwood, crepe myrtle, etc.).
Curtain Panels

Curtain Panels

More mystery plants!

More mystery plants!

My garden thus far

My garden thus far

Problem peas

Problem peas

Lurking.

Lurking.

I love Blue Salvia

I love Blue Salvia