I can't speak to what will grow well in your specific area, but what you're describing sounds like it will probably be a type of Juniper. Some Arborvitaes have a tendency to loosen up with age. Explore the columnar versions of Juniperus communis and J. scopulorum. I can understand why you might not want a plant that leans yellow, but not why you're avoiding those that lean blue. It's a classy color range.

Thanks for the input, Yardvaark.

"I can understand why you might not want a plant that leans yellow, but not why you're avoiding those that lean blue. It's a classy color range."

It's funny you mention that--because blue is actually my favorite color. But the blue-green trees of the type I'm looking at always seem to be more on the gray-blue end of the spectrum, and look kind of dull. Also, a rich green color would fit better with the other trees and plants on my property; they'd give a more cohesive look.

You are in a classic climate for Italian cypress, Cupressus sempervirens, the standard for tall, skinny evergreen conifers :-) And there are all manner of arborvitae that would work for you -- without the issues of frequent snowloads, these tend to hold together very well and are the go-to narrow evergreen screening plant in my area. Thuja occidentalis 'Smaragd' is the cultivar of choice.

IME, upright junipers tend to be far less columnar than you appear to want - most will develop a good-sized, squatty bottom or become distinctly pear shaped. If you want to go through the maintenance involved, Leyland cypress can make a spectacular solid evergreen hedge, providing that solid dark green wall you want. But will take a lot of pruning/shearing to remain so.

Thanks for the great input, gardengal48. Very helpful!

As for maintenance, honestly, the less there is to do, the better. Ideally, stick them in the ground, water as necessary, and that's that. I'd really prefer something that won't need any kind of pruning/trimming.

Then stick with the Italian cypress or the arbs :-)) They start narrow and stay narrow. Minimal to no pruning required.