I've noticed them in our area as well...they tend to hide behind all those ladies bending over, forcing out the beautiful flamingos. Why I have even seen them overtake the orange pumpkin bags near Halloween...very tough cultivar to eradicate.
I heard they're resistant to round-up, too. Maybe some black plastic mulch will be able to smother them. I think we need an integrated gnmome management program in place. Know any good sources for grants?