WordNet sense 1 (ornamental shrub or small tree of swampy areas in southwestern United States having large pink or white sepals and yielding Georgia bark for treating fever):

bitter-bark, Georgia bark, Pinckneya pubens

WordNet sense 2 (tall fast-growing timber tree with leaves containing a medicinal oil; young leaves are bluish):

blue gum, Eucalyptus globulus

WordNet sense 3 (African tree supposed to mark healthful regions):

Acacia xanthophloea