Answer: Your Colorado Blue Spruce trees can reach a mature height of 40 to 60 feet high, 10 to 20 feet wide. The roots will most likely be concentrated in the top 18-24 inches of soil and extend out one and a half to two times the diameter of the canopy. I'd plant them as far away from the leach lines as possible (so you don't invite problems down the road), and space them 20 feet apart.
Best wishes with your new trees!
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