They advertise some customers get it done in two cuts. But as usual, it depends on when you cut and the size of the rhizomes. But if you hit it right, and get the Spring bloom, it really drains the rhizome down on that first cut. Then it has to draw a bunch of stored energy to start all over. When you cut that it is usually last gasp all or nothing growth. The rhizome is so depleted it just can't survive another push and either succumbs to disease or just shrivels and dies.
It's a different cut on bulrush and cattails as I want to get them as deep as possible to force them to grow all over again. With lilies you can cut just under the leaves. Real shallow. And about triple the speed, as the soft stem is nothing like those hard stemmed bulrushes.
