Vitex agnus-castus

[Desert O'Piñon]

I picked up this Chaste Tree at our local zoo/state park in April for $7. I divided the three trees into individual pots, and these two -survived- thrived. They have gentle inborn trunk movement, and I think they have a lot of potential.
Being too dense to learn from my mistakes, I acted before researching, and I cut these roots back at the bottom of the pot.
So, did I kill my tree, or was it the right move? Would it have been better to repot in the hottest part of the summer?

 

[Desert O'Piñon]

Unintentional leaf reduction on the tall one, after cutting the roots from under the container. I think the top-heavy pot tipped over in a breeze, and I didn't notice until the day after. The roots were not completely dried out, but it suffered enough to trade its leaves for its life. These are the new leaves in the upper part of the photo, versus the original leaves on the other tree, which were the same size.
Seems a pretty dramatic difference to me.