Question
I have a 4th floor roof -top deck garden with flower boxes and other containers.  I have planted a variety of plants in the past month and some are flowering.  The lobelia and the petunias flower and then a 'varmint' eats them up.  The first time it was just the blossoms.  I put cayenne pepper on the plants and they started to bloom again.  The rain came and washed off the pepper and when I got home yesterday from work, my entire petunia plant was gone.  There were a few pieces of leaves on the deck.  Again, the lobelia flowers were gone, but the rest of that plant was intact.  Do you know if there is an animal that particularly loves those 2 plants?

And if so, what should I do?

My other plants have not been touched.  

Answer
Without more information, It would be hard to make a specific species diagnosis. But culprits that I am thinking of include birds, squirrels, rats, mice, cats. I don't know which species you have seen on the top of your roof.
How you protect your plants depends on what is causing it. If cats, keep them off roof. If birds, then netting is the way to go. If squirrels, then cage netting or trapping. Visit http://www.wildlifedamagecontrol.com/solutions.htm for damage control solutions for a variety of species.

I would appreciate photos. They can be e-mailed to [email protected]