How much rain do you get annually?

Around 40in a year

Why would it be dry? Isn't there any soil?

It’s ornamental rock

You want to plant it in a rock pile?

tj

It is not a rock pile. It is just a xeriscaped area

Oh wait nevermind, there is soil under the rocks

I don't know how big of a tree you're talking about but it's important to get as big of a root ball as you can handle. A larger tree could be quite large and require a hydraulic loader or the like.

Picea glauca is drought tolerant to a point, after it is well established. It prefers consistently moist soil but will endure a dryer area if you keep it moist for the first year or two after planting, if no rain.

A dug tree can take 3 years to fully establish. The bigger the tree and how badly the roots were butchered when you did the digging, will determine how long it takes for the tree to replace the roots that you left in the ground when moving.

Mine have survived some pretty dry summers the past few years but one of the smaller ones lost its top 16" due to it getting too dry several years in a row. It has recovered since.

Water and get a good root system established for a few years, and it should be fine.