Neither do I like lawn edging or black plastic. I have daylilies in front and back of a black board fence, and this area is bordered by grass.
I dig a deep trench below the grass roots and extending about 12" beyond my plants' base.
I then fill the trench with mulch and mulch the plant.
The last step is to work Preen into the mulch as directed and water it in.
This process usually lasts two years for me before I need to tidy up or re-dig the trench.
Of course, I replenish mulch and preen yearly as needed.
