A guy a mile or so from me has west facing lawn banks in front of his house planted with irises. Grass has grown between them because he does no weed control at all. They are cut down with the mower in the summer after all blooms are finished. He leaves the foliage in place for maybe 3-4 weeks presumably to let the rhizomes build up. They are mowed weekly the rest of the season. Those irises seem to grow anyway! Too drastic for me but tempting.
mbl8000 
