Large stands of blue gum and river red gum planted for windbreaks can be found from San Diego to Redding. Various eucalyptus species populate virtually every lowland area of California. There are more than 500 species of eucalypts in Australia, occupying many different habitats. Eucalypts are absent from the dry interior of the continent except for where they find refuge in a few isolated mountain ranges or along intermittent streams. Eucalypts dominate high rainfall woodland areas while some extend into drier inland areas.
Some species grow along riverbanks and in flood planes.
Although many species of eucalyptus appear to grow well in California, few are well adapted to its and climate. California's climate is much like that of the Mediterranean where the summers are dry and the winters wet. Thus, most species, unless irrigated, suffer varying degrees of drought stress during the summer. Susceptibility to borers and other pests greatly increase when trees are stressed by drought. Nearly all eucalyptus species will benefit from regular and thorough irrigation during the summer.