I also live in Reno, elevation 5000 ft.
with Sumire. My low temperature this year was 10 but rainfall total is .25 inches (that's 1/4 of an inch in 6 months) since the big rainstorm at the end October. I water every couple weeks all winter. Reno sand is not very moisture retentive - shallow rooted plants suffer the most but even the trees need a drink. Have you noticed how many dead pines we have this spring?
As for evergreen vs dormant type, it doesn't matter, they all die right down to the ground anyway.