... At my age, it's FAR too much work to try to keep it cleaned out with a weed whacker so I just live with it.
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Cost is a factor, I'd spend $500 or so for a good solution. Maybe more for something really elegant and PROVEN to work.
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Find a lawn service already working in your area. Have them trim it once a month during the growing season. Spend your time on something you enjoy.
Bruce