Generally, the best time for planting trees is late winter through early spring.
Snippet: The best lettuces to grow in wintry mountain gardens. Attractive lettuces make attractive landscapes in every season.
We’re ready, let’s get to Spring! 
Governor Ducey, ADOT Urge Drivers to Know Snow Before Trips
Arizona has Nearly 1 Million Acres Statewide of Commercial Agriculture
Avoid cutting back autumn flowers that shelter local birds from cold.  Plants that attract more birds.  Perennials that provide seed and shelter. Illuminated holiday evergreens help birds.  
Winter is coming, but you can still have home-grown herbs.