I have 5 apple trees that I bench grafted in 2021 and planted in the ground in fall of 2021 and trained to Belgian fence. In 2022 they were covered in flowers and right after that with fire blight. To make long story short, I had to cut 4 of them to the rootstock in fall when I transplanted them to a new home and hope they survive to be regrafted in spring with fire blight resistant varieties. The one that survived has following shape.
I am planning to keep this variety and make this tree a regular espalier now. Should I collect the scion in February from it, cut it below the graft union and regraft next spring , or use that vertical shoot as is as a new trunk?
Thanks!