I have an inside grow area that would house them for the winter.

You must have missed part of my earlier reply, or perhaps I didn't send it as I
thought. Desert willow is a temperate tree and requires a dormant period, but
it is not very hardy, only to about Zone 8. So you will have to find an area
where it will be kept cold for 2 or 3 months, but not much below freezing.

Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)