Peruvian Lily Under Attack
 

I have a peruvian lily that I planted in the ground last fall. It's
starting to spread a bit and was looking good. Today I took a close
look to find it covered with ants, and what I believe was a flower
stalk had been nipped in the middle, causing it to fall like an axed
tree, it's leaves/buds completely denuded. The sword-like leaves all
seem to be rather droopy now instead of firm. My questions a

• Could the ants be responsible for the damage? I didn't see any
aphids, so why would it be infested with ants?
• Are peruvian lilys a favorite food of slugs, or what else might have
damaged it?
• Any tips for growing this plant out in the garden (Zone 9)?

Thanks.

-Fleemo