Answer: The most effective method of eradication would be to dig the entire bed, removing weeds and weed roots as you go. Then replant the desireable plants and place a weed barrier over the top of the soil. You can then cover the weed barrier with decorative rocks or bark. While it sounds like a lot of work, once it is done, it will remain weed free for years. It's much safer than using chemicals; vinegar will kill the tops of the weedy plants but they will continue to sprout up again and again. I'd just roll up my sleeves and do the job. Your dear friend will thank you for many years to come.
Best wishes with your project!
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