We have three phormiums in a row. They are a muddy mid-green and are about three feet tall and the same wide. They must have been in place for at least five years, but probably much longer. We'd like to get rid of them and lay a lawn there. Do we need to dig them out or can we just weedkill them and turf over the dead roots? There's nothing around them that would be damaged by glyphosate. The lawn does not have to be perfect.

Thanks.

Laura