Downy myrtle is now reclassified and called Rhodomyrtus; Myrtus communis is the proper name for the plant commonly called Myrtle. Neither is entirely hardy, so if you don't get heavy frost where you are, its worth a try, but you may lose them all in a prolonged cold snap.

I lost my myrtle but my cousin who lives 3 miles away has a thriving myrtle bush planted in a south-east facing corner where it rests against the walls. It is beautiful every year. Mine was in a more open position and failed to thrive.