Answer: Voodoo lily is botanically Sauromatum venosum, which is a member of the Araceae family. The inflorescence is interesting and even beautiful, especially in groups, but the stench is awful. Unlike some aroids which smell like carrion, this one emits a pervasive reek of rat feces. But, that doesn't sound like it is the Arum you're growing. Arum family plants include the commonly grown cuckoo pint, and Lords and Ladies, and are grown for their ornamental leaves and attractive spathes, each enclosing a pencil-shaped spike of tiny flowers. What you are describing sounds more like Amorphophallus titanum or Dracunculus vulgaris. Wish I could help more with the identification of your plant.
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