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. Most can tolerate some summer drought, though, and will adapt quite well to California gardens.
Australian soils are usually quite lean.
These nutrient preferences are probably the second most important reason why Australian plants fail to thrive in American gardens, the most common reason being susceptability to root rots, primarily Phytophthora. In general, almost all Australian plants can tolerate light to moderate doses of fertilizers as long as they are low in phosphates. Most California soils are rich in phosphate by Australian standards, and supplemental applications will usually hinder growth. Such applications can even be enough to damage or kill plants. Phosphate toxicity is indicated first by interveinal yellowing of the foliage, followed by blackening of the leaves and twigs.