A garden fence marks ownership without containing everything that grows across it.

Boundaries are legal facts that living things ignore. Roots run under the line, branches lean over it, seeds land wherever the wind puts them, and the plant that belongs to you by title may be feeding on soil that does not. Ownership describes who is responsible and who may decide, which is useful, but it never quite describes what is actually happening. A great deal of neighbourly friction comes from expecting the two to match.

Where a boundary in your life is being enforced hard, ask what is crossing it anyway. Then negotiate about the actual growth rather than the line on the plan.