The Pacific Northwest area of the North America includes the northern area of California, the states of Oregon and Washington and the southern area of British Columbia, Canada. In this rather northern region, the climate is moderated by warm Pacific Ocean currents which allow a very wide range of plant material to flourish. Many plant species were "discovered" by European plant explorers in this region and were then introduced to the rest of the world.

Map of the United States.
See some of the gardens in the United States.