You oughta just mow them all down. You can cut that plant all the way back to the last leaf node and it will sprout again no problem. It's real easy to root the cuttings too with the cut end suspended in water.
I'm planning to mow it all down. I kinda want to grow my crypts out again so I may end up moving them over to my 40B for the meantime. It was an awesome experience with these riparium plants Devin. That I have you to thank for!