Echinocereus arizonicus seed came from cultivated plants that came from the type locality in AZ. These have done well in our garden but definately need the drainage to survive. They are more touchy than the other claret cup cactus but not any more difficult than echinocereus engelmannii. Plants have taken -17F but good drainage and a nice microclimate is suggested.
I do not guarantee these in a zone 5/6/7 because everyones growing conditions are different but this would be a good trial plant to grow in your cold outdoor garden. Try to plant outdoor 90 days before 1st hard freeze.