About 2 year ago, I had a large (3-ft diameter trunk) ant-infested locust
tree taken down from my front lawn. Now, two years, later, there are
literally hundreds of locust trees growing all over the yard.

I presume this is from the root system that was left after the tree was
removed. I am trying to figure out what to do. Roundup does no good at all
on these things (it kills it, but it also kills all the grass around it).

Any suggestions on what to do to eliminate the problem?

Thanks.

H