Answer: Prescott is considered zone 2, according to Sunset Western Garden Book. These zones are different from the USDA zones, and are much more accurate for the western states because they take into consideration elevation and ocean influences that create microclimates within California, Arizona, Idaho, Washington and Oregon. Expect snow in the winter with average winter lows between -3F to -34F. Of the plants you mention, rhubarb will grow well in your new garden, peonies will adjust (they don't like to have their roots disturbed, but will recover with some TLC), and Dicentra will grow nicely. For additional ideas on what to plant, pick up a copy of Sunset Western Garden Book. It's a wonderful reference!
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