I use the fruit from this tree/hedge to keep spiders away from the house. It works really well for that. I would say it is safe considering it grows all around and wild treefrogs such as grays are exposed to it. There is a bunch of hedges on my neighbors property and I agree they are interesting looking and would make neat specimens in an enclosure. Maybe if its natural state is altered by certain chemicals/treatments it may be harmful, like you said it is made into a dye, but just as is would probably be alright.