Palmetto does very well in both sunny and shaded areas, but truly stands out because of its shade performance. Most grasses will not do well if they are left in the shade for the majority of the day, and Palmetto can stay green and lush with just 4 hours of direct sunlight a day. It also stays green long into fall and begins greening soon in the spring. It will take several heavy frosts to make it go dormant.
Palmetto St. Augustine is best for Phoenix homeowners with heavily shaded lawns who want their grass to stay green as long as possible and don't want to overseed in the winter. Palmetto doesn't do well with overseeding, so being able to accept a brown lawn in winter is something to consider.