When I put in NWSGs, I had one 5 acre field taken over by those things. When the fescue was killed, the Maypops immediately sprouted and kept the NWSG seed from germinating. I talked to the guy at the seed company where my NWSG seed came from and was surprised that he was interested in getting the seed pods. I told him he could have them. He sent 6 workers who filled a horse trailer and two full sized pickup truck beds with those pods. The leaf springs on the pickups were flat from the heavy load. Afterwards I had to spray and start all over. They are perennial vines that come back from the roots every year. Unless there is something bigger and badder to overtake them, they will persist. 24D is effective.