I decided to take the risk and repot the large field-grown Scots pine I bought last year as knew that it needed to have the old soil removed for it to really thrive. It has had a good year with plenty of food and water and was strong enough to deal with the trauma of the transplant.
I allowed the soil to dry for a few days as its much easier to remove than if it was wet and muddy. The tree and old soil was very heavy and hard to work on - leaving my hands covered in blisters - but it was the right moment for the work with the new growth just starting to swell. The big risk is that the trauma will loose me some of the top quality back budding that developed last year.
The old soil from field growing contained heavy gravel and some chunks of flint. There were large dry sections with no roots because the rocks and heavy soil made it hard for the water to penetrate the dry areas. I hope it won't be too upset with the bare root treatment - I have waited until the perfect moment to repot it and based on previous experience it will continue to grow as if nothing has happened. The improved breathing and watering around the roots should give a useful boost in vitality as the season progresses.
Once I had cleaned off all the old soil I could see that 2 major roots were growing upwards which couldn't be removed now. Once the rest of the root ball is mature enough they will be dealt with. The surface roots at the base of the trunk will then be quite good.
The clean root ball was still quite nice. I had spent a few hours cleaning out the old soil and trying to damage the roots as little as possible. I also didn't want to use water pressure to clean the roots as I wanted them to hang onto as much of their beneficial fungus as possible. I also added a few sections of old roots to the bottom of the new pot to help the fungii even further.
I took a chunk off the bottom of the lowest taproot to seat the rootball deeper into the pot. Once it was positioned I began gently filling and working into the gaps making sure there were no air gaps under the base. I added further soil in by layers and worked it carefully around the roots. Filling the pot in one giant pour and then poking it frantically with chopsticks ends up traumatising the poor roots.
The large training pot is from Kaizen - and the soil is all the usual stuff. The draining layer is large Canna clay pebbles. Then its supalite and pinebark with a bit of fine biosorb.
Some of the roots above the soil level will be trimmed off in 2 years time once the roots below soil level have caught up.
A few big chunks of root removed were removed - none close to the trunk - all from the ends of the roots where they had formed heavy nodes at the edge of the pot.
I lowered the soil level around the base of the trunk in preparation for the next repot in 2 years time. I intend to lower the soil level by about 1 inch at that time to bring the whole pot down to the level that the soil is against the trunk.
The tree was then watered heavily to clear out the dust and settle it all in. As per usual I watered with canna rhizotonic and light organic fertiliser to help the roots recover. I will be watching anxiously over the coming weeks to see that it recovers.