Tidy growing spaces are a humanity-created expectation about how to be both productive (farms) and esthetically pleasing (city/town gardens). The culture one grows up in will determine how intensely the keeper of that growing space will interpret “tidy”. Farming has the priority of maximizing plant health (and therefore production) through understanding long-term soil health (not so true in mechanized farms) and so a "system" arises from experience and is passed down through generations and cultural norms.
Gardens may have some vegetable and fruit production but are primarily for visual pleasure and showing care of the home and garden for individual "peace of mind" but mostly to show societal recognition that says the homeowner is a caring person. This has led to "standards" and tidy is the minimum expectation. If a house and its gardens are not being cared for, we interpret this as "unhealthy" and that it will likely lead to deterioration of the neighborhood on so many levels—including an increase in crime.
Tidy is therefore the minimum. Tidy requires some skill and experience but also time availability which is especially an issue in the gardens that are street-facing and so not a private experience. We see this when driving through neighborhoods—all the gardens look pretty much the same with minimal creative effort, as they are for viewing but rarely for sharing time with neighbors or visitors.