Neighbor's windows looking into our backyard are from 2 bedrooms, dining room, and laundry room. I suppose privacy is only 30% of the concern and the rest is visual interest. Imagine walking out of the backyard and the first thing you see is 2 story home with those windows I mentioned.

I totally understand! It can depend on what zone you're in. I have suggestions, but we're in Southern CA which might not help. Best bet is go to a reputable nursery and ask for suggestions...and take photos of the area in question.

I happen to like Carrotwood trees for various reasons...evergreen, appearance and cleanliness. They've worked nicely for us and other people we know here in SoCal.

Our neighbor behind us planted a row of bamboo, which grew quickly and is pretty. We cannot see their windows at all now. We are in Oregon. Good luck!

Many types of bamboo are invasive, and planting them is forbidden in most places. Check before going that direction!!

Thank you all! We're in Eastern Washington state which is Zone 5, I believe.

Clumping bamboo isn't invasive, but it does shed the leaves so maybe not what you're looking for. Perhaps consider shade sails instead?