To mend fences is to put a quarrel right and be friends again. The visit was an attempt to mend fences.
It suggests patient repair rather than a grand gesture, which is usually what works. The picture is a farmer walking the boundary and fixing what has broken.
1phrasemend fencesTo put a quarrel right and be friends again.
“He went round at Christmas to mend fences with his brother.”
mend fences is a phrase.
Practised in Idioms