Experience with bougainvilleas in California, Oregon and Florida indicates that, in general, they are deer-resistant plants and they won’t be eaten, but if other food is scarce deer will ignore the nasty spines and the distasteful leaves and feed on them. As always, a deer fence is the best approach to preventing deer damage but, in warmer zones where bougainvilleas make large and vigorous plants, gardeners often tolerate a little deer browsing.