In the United States, olive trees are grown commercially in California and Hawaii. However, you can grow olive trees in your garden in USDA zones 8--10, where there are hot, dry summers and mild winters. The best locations for growing olive trees, however, surround the Mediterranean basin. Greece, Italy and Spain are the largest producers of olives for domestic use and export. North African countries such as Morocco and Tunisia, and Middle Eastern countries such as Syria and Lebanon are also big producers.