Dig out the area and replace the dirt is the only thing I can think of.
Personally I'm trying to get some established in a pot in my pond

Shell


"mulroys" wrote in message
...
I'm afraid that my yard is overrun with the things. They are quite
prehistoric, and I actually have a shale fossil of a plant that is very
similar.

I've been pulling them for a year, but if I leave the tiniest bit of root,
they just grow back.

I've tried paraquat, glyphosphate, and 2-4-d. They seem to enjoy it.

I don't want to use a soil sterilizer, but I'm stumped.

Thank you in advance