Answer: If these are perennial weeds, you may need to grub them out by the roots or spot treat them with an herbicide containing glyphosate. To prevent annual weeds such as crab grass, you could treat the walkway with a pre-emergent such as corn gluten. This should be applied very early in the spring, about when the forsythia bloom, because that is when crab grass starts to germinate and reapplied during the season. After applying a pre-emergent you need to avoid disturbing the soil surface. With any product, be sure to carefully read and follow all of the label directions. Also, regular raking of the gravel will prevent new seedlings from growing. I hope this gives you some ideas.
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