Ok, so I've discovered that Aqueliga, because it grows so early in our garden (WD3), seems to drown out the little ground elder shoots coming from inside (yes, literally inside) the fenceposts this year. This means that they never made it to full leaf, therefore hopefully no chance to store the energy to become a real problem. Now the only question that remains is whether I replace the whole lawn with Aqueliga. Not likely, ho hum...