In this catalogue we have made an effort to list the origin of the plants for those who know or are learning about the biogeography of Australia. The northern regions of Australia are similar to our southern states in climate, except that northern Australia is deeply tropical. Occasional rain is common there during the summer. Overall, however, the climate is still Mediterranean in nature. The lower half of Western Australia has a climate that is very similar to that of Central or Southern California.
Winters are somewhat wetter and warmer.
Perth gets an average of about 40 inches of rain a year, and civic landscapes commonly include cultivars of Pimelea ferruginea and Chamelaucium uncinatum, plants which would not survive in many areas in California without winter protection. In all areas, the farther away from the coast one gets the hotter the summers become and the colder the winters will be. Plants from the Nullarbor Plains or neighboring regions on the southern edge of the continent will tolerate extreme conditions. Tasmania, off the extreme southeastern tip of the continent, has a more maritime climate. Many plants from that island can take heavy freezes and even continuous rain.