Another view. The property line is on an angle. Again, the valley is throwing me off. I was thinking a blue shaded pine tree right next to the rock wall? I like "modern" design and plants. If that makes sense. Definitely need somethin talk. Maybe a popular? Forgot the name, but it's thin and tall

sakura

Lombardy poplar, and no, just no. It's a short lived tree and will create a mess almost the day it is planted. Try looking for a "fastigate" (upright) evergreen that can tolerate some shade. What is your zone?

Zone 7. New Jersey. I don't really want to go the pine tree direction, but thinking about it...

Cool pic! I'm pretty happy with the current sidewalk and blue atlas spruce though. They block the view that would otherwise be staring straight up the street! I love the blue spruce location you added on the right. I may work 2 in that area. They're contained enough that they won't look overbearing. But can pinpoint exact areas to block too.

Blue spruces get huge and wide. There are some smaller varieties out there but uncommon. Try looking for a Serbian spruce, Picea omorika, it is much narrower.

Note: you have a lot of trees on your property. Whatever you plant for "view blocking" will have to tolerate some of their shade and have foliage that is lower to the ground than the tree branches. That's why I'm suggesting an evergreen. Some shade tolerant evergreens are arborvitae, yew, and dwarf hemlocks (not the common hemlock, the dwarf stock). Also Serbian spruce to a small extent, which is why I suggested it. Another is concolor fir. Neither the fir or spruce are very shade tolerant but will grow in some light shade.