Humans will accept something that looks like it is intended, while they will reject the very same thing if it looks unintended. The border can be lawn, or a hedge or a fence. It can be a series of low native plants, or a stone or woodchip path. It really doesn't matter. Remember that although you have a right to your coneflowers or prairie grasses, your neighbor has the right to clipped lawns, plastic geraniums, and cement lawn deer.
Nothing repulses more than arrogance.
Don't be an arrogant natural landscaper. Don't be a self-righteous natural landscaper. Remember that you are a pioneer who is trying to win converts, not a martyr willing to go down in a flood of litigation and neighborhood disgust. Natural landscapers who consider themselves better than their neighbors serve only to undermine their own cause. If you tell your neighbors why you're tearing up the lawn, or planting native plants, or constructing a water garden, chances are that they will accept it.