A friend just gave us a potted camellia plant as a shower gift, and I promptly stuck it in the ground in a sheltered spot in front of my house. It looks great, but every day or so, though, I come home to find a flower or two dismembered on my front steps. I know that deer like to eat them, but I’m pretty sure there are no deer in my neighborhood. Does anything else have a taste for camellia blossoms? Squirrels, birds, cats, the teenagers next door? What can I do to defend my lovely plant from these marauders?
When you say you’re finding a single flower “dismembered” on your porch, you mean you’re finding the flower all torn up in pieces? Shredded, like?
I wouldn’t think that a deer would do that. Wouldn’t a deer ingest the flower (“nibble, crunch, gulp”), not pick the flower, carry it over to your porch steps, and shred it, leaving (apparently) the majority of it in pieces?
My guess would be, from the suggested list, “teenagers”. 
What can you do? Set up a hidden videocam in the living room window focused on the porch, would be my suggestion.