Ginkgo Bonsai trees grow well in the high desert plains of Colorado. Pre-Bonsai trees are able to over winter in gravel bunkers and without any complications. Finished trees should be over wintered in a cold frame such as a garage. The Denver Botanic Gardens keeps their Gingko in heated greenhouse.

I have started a  Gingko Bonsai page in the Tree Information Page under Deciduous Trees section of the website.