Check about that particular species, but I planted my Carolina Sapphire trees in the spring, and watering them all summer is gets very tiresome. I planted my evergreen privacy hedge (wax myrtles) last October, watered a half dozen times, and then the winter rains took over from there (40+ plants). They will establish some root structure over the fall/winter months.
Glad I timed it right, else I'd have had to install a drip system or endured a 300 water bill over the summer months.
Ruckus, I forgot to mention, in my search for the Carolina Sapphires, I learned that the Leland Cypress is susceptible to a irreversible rust colored blight