The Safer Insecticidal Soap label says do not use on lilies. But, not realizing this, I have sprayed lilies with insecticidal soap before. They seemed fine. But if I need to do it again sometime, I think I would switch to neem oil, just to be more safe.
Lucius, if end up planting candidum in different kinds of soils, it would be interesting to observe any differences in growth in them.
