I too have the ash seedling problem from a single female ash in my patio area, literally I pull 1000 of them from my mulched garden weekly in the spring. I sweep up thousands from the patio weekly, vacuum seeds up from the rocked areas. I've dug up plants 3" tall and found a tap root 10" long. Any larger plant requires I dig below the wide root area, presumably the root ball, and then I pour boiling water into the hole to kill off the root. I've not had any regrow. I'm considering removing all the leaves, seeds, and mulch down to the dirt, each spring, and replacing the mulch. Or I might use pavers to decrease the mulched area. Or would it be better to leave a thick mat of mulched leaves to suffocate them out? To rake or hoe them around to discourage them from sprouting? To lay down screens to catch seeds and leaves so I can leave the mulch? PS I've found the boiling water method useful for killing trunks too, and it makes them dry rot quickly.
