dave said:it's so aggressive for us that I had actually always been under the impression that this was an invasive plant.
I think the term that you are looking for is "weedy"...
I think you should employ the strategy that I use with ragweed... pull before it blooms...
And then be thankful that you aren't dealing with phyllanthus urinaria or Fatoua villosa... both of which sets seed almost as soon as they come up!
Annuals generally are just not that problematic...
