Buxus - Potting up a nursery tree.

I bought 10 of these Buxus trees a few months ago because most of them have very nice nebari and with that very cheap:

The trees were very leggy so I cut them back to the lowest possible branches/twigs with leaves. I used the water hose to remove some top soil because there were very little surface roots and replaced the washed of soil with horse stable compost. The compost on top of the soil:

The trees budded out nicely:

Two weeks ago I started to reduce the height of the root balls of the trees.

I first cut back the tree again to twigs with green leaves and I also sealed all the wounds:

Nice surface roots have formed:

I decided how much of the root ball I wanted to keep and took an old saw and saw of the bottom three quarters of the old root ball:

Saw through, plastic removed and a big root sealed:

I layered the new plant pot with a free draining medium of about 1cm and also 2cm of my normal mix - I need new roots to form lower down because I will have to remove some surface soil later on to expose the nebari.
The tree placed in the pot:

I added some soil to the sides and finished it off with some compost:

It was watered heavily and placed in light shade to recover.