I am planning to plant two Pear trees, Conference and Doyenne du Comice as espaliers against a 2m tall, old brick wall. (supplied as maidens on Quince A rootstock)
I know that conventional fruit tree planting practice is to dig a hole 2ft x 2ft x 2ft, centred 18in away from the wall, remove subsoil, incorporate rotted compost with topsoil when refilling hole. Plant Pear into this. Mulch.
I have also read Charles’ words on planting fruit trees.
Unfortunately, and probably very typically, when I have started to dig a hole 18in away from the wall, I find that the site had been used by the Victorian builders as a tip: half bricks, broken hearth tiles, broken glass. I don’t know whether to go down the conventional route (2ft x 2ft x 2ft hole) to get rid of the rubble, then replace with a mixture of topsoil and rotted compost.
Andrew I would leave all that stuff there, it has become part of your soil, full of organisms I expect and your best route to improve matters is surface organic matter.
So make a hole large enough for the tree roots (Not necessarily 2ftx2ft, may be more or less, backfill with soil only and then organic matter on top.
It has worked well here on builders rubble. My whole small garden is like that.
Andrew, I planted two espalier apples three years ago against the wall of an 1700’s stone building. It was exactly as you describe – full of all sorts of rubble. I planted bare rooted one year old whips into holes as Charles recommends (just a little bigger than the roots required) and the trees have done very well. Each year in autumn I mulch with well rotted manure.