A recently read about some guy who had spent an entire summer plucking out, by hand, all of the Japanese grass from a Pennsylvania field. That struck me as about a big of a waste of time as I've read about, given that:
1) The grass will just move back in the next year;
2) At that rate, the guy will have covered, what, .01% of Pennsylvania by the time he dies; and
3) "Invasive" species actually increase biodiversity:
'“There is no evidence that even a single long term resident species has been driven to extinction, or even extirpated within a single U.S. state, because of competition from an introduced plant species,” Macalester College biologist Mark Davis notes.'