Hi Clyde, You would have thought an electric discharge through the weed would have killed it , I'm guessing this is what weeds do really well ... loose their tops , and then grow even stronger. we have a weed called Mares Tail, nothing seems to kill it , leave one mm of root and its back, same with Convolvulus , some chemicals may work but either poison the soil for many months , or are illegal , I think a few 'shocks' on a regular basis may work, or up the volts / current , as most plants (weeds) need leaves to feed the roots. Actually feeding weeds with very high strength fertilizer can also 'exterminate' the perishers.