To my great delight, one of the plants I see most often in Rome also grows well here in California: Cyclamen. With heart-shaped leaves and charming pink, white, or red blooms, Cyclamen come in twenty different species and are native to parts of the Mediterranean including Turkey, Greece, Lebanon, Libya, and Italy. They are annuals that like part-sun and live for many years even in containers.
In Italy, you often find Cyclamen in pots, flower boxes, and planted around trees. They are beautiful in the summer, but they are particularly spectacular in winter when they bloom prolifically for months. It isn't unusual to see cyclamen blooming outside in January in Rome -- and even in Florence during milder winters.
Here in California, my little plants pant all summer long waiting for the cooler days of autumn when they burst out into a riot of color. They bloom clear into spring and are often the only spot of color in my winter yard. I also grew Cyclamen in Minnesota where they bloomed all summer and sometimes through the winter when I brought them inside and kept them in a sunny window.
I was just at my local garden shop today, and the shelves were full of Cyclamen in several shades. I'd imagine I'll be planting a few more this weekend, too.
For more information about Cyclamen, check out the Cyclamen Society.