http://en.wikipedia.org/wiki/Prunus_tomentosa

I have my doubts ... it thrives in the British isles, Tibet and Japan.

Why did you buy them before you knew what their growth requirements are?

Everything I have read said it is heat and drought tolerant, tolerant of pour soils and requires full sun. Last year when I was researching I remember someone said they were growing it in Arizona. I just don't remember where they had it planted.

Sunset's Western Garden Book lists it for the following zones: 1,2,3 and 10

That's northern and eastern AZ, in the high country.

Dave's Garden lists it for the following zones.

Hardiness:
USDA Zone 3a: to -39.9 �C (-40 �F)
USDA Zone 3b: to -37.2 �C (-35 �F)
USDA Zone 4a: to -34.4 �C (-30 �F)
USDA Zone 4b: to -31.6 �C (-25 �F)
USDA Zone 5a: to -28.8 �C (-20 �F)
USDA Zone 5b: to -26.1 �C (-15 �F)
USDA Zone 6a: to -23.3 �C (-10 �F)
USDA Zone 6b: to -20.5 �C (-5 �F)
USDA Zone 7a: to -17.7 �C (0 �F)
USDA Zone 7b: to -14.9 �C (5 �F)
USDA Zone 8a: to -12.2 �C (10 �F)
USDA Zone 8b: to -9.4 �C (15 �F)
USDA Zone 9a: to -6.6 �C (20 �F)
USDA Zone 9b: to -3.8 �C (25 �F)
USDA Zone 10a: to -1.1 �C (30 �F)
USDA Zone 10b: to 1.7 �C (35 �F)

I guess next summer I will find out for myself one way or another.

Anyone successfully grown "Prunus tomentosa", aka Nanking Cherry and a host of other common names in Maricopa Co. or areas like it?

I am fairly confident it will grow well here. May be some sunburn issues its first year. But based on its reported growing environments I suspect it will do well here and be an attractive ornamental hedge.

But I suspect the chill hours will be inadequate for fruiting or flowering????

Anyone with experience?

Have you had good results with your bushes? I just bought 2 bushes for my property down south (Sunset-10) & was wondering how yours were doing here in the low desert.