I have never before managed to get Madonna Lilies to thrive in my garden. Usually I hoe the buds off in Springtime when they are just appearing above soil. This puts paid to any flowers for a year. If they make it past this stage, I find they usually get eaten by slugs or something. I don't know what eats them, but it completely removes all growing parts, leaving nothing behind except small black turds and the stalk.
These Lilies came up under my trees this year, and it has been so long since I planted them that I had forgotten what they are. I thought maybe they were Fritillarias. Anyway, this year when they came under attack I drenched them in insecticide and surrounded them with slug pellets and they have now flowered. A first for me.