The rest of the plant is considered to be slightly toxic. I don't know the answer to whether or not a rabbit would nibble on it.

I have had good luck with castor bean plants in containers. Make sure it is a large container. They will not get as big as in the ground, but still very tropical looking on a deck. I was just given 3 very large kitty litter pails that I will spray paint forest green, drill a couple drain holes in bottom and start some castor bean plants for friends.