My regiment is to spray the lilies with Plantskydd as they come up and about a week later. The area around the lilies also has spray residue, and I am sure that impacts the area's scent as well. It's something that I have found success with, so I stick with it. We have lots of deer around here! Plantskydd also works to help prevent the winter damage that can happen on newly planted trees. I spray those in November and coverage lasts 6 months.
