We use high-voltage electricity, applied through an electrode in contact with a plant, to electrocute the unwanted plant. The current which flows through the plant and root system effectively boils the root system and causes permanent damage to the weed. Where the roots are destroyed in this way, regrowth is prevented.
Electric weeding kills weeds systemically even on hard surfaces. Self-bonded gravel is a particularly tough surface to remove weeds from. The left picture is the path before treatment (with untreated beds adjacent), the right picture is the path 30 days later. All the weeds on the bonded gravel path have been eradicated, but weeds in untreated beds continue to grow.