best tree for barrier/living fence
We live in a mid-century modern home (1954) with a wall of windows that (now) faces a giant mcmansion to the north. We intend to plant a living barrier, not only for privacy/blocking out our neighbors a/c noise, but also to create an enclosed garden area. Emerald Arborvitae has been recommended and is most likely what we will go with; however, I wanted to ask the forum if there might be a slightly taller alternative out there. We don't want 50 feet tall, but 20 to 25 feet would be ideal. Since we are planting right near the property line (with our neighbor's consent), we do not want to go too far over 5 or 6 feet wide. Does any kind of evergreen exist within these dimensions? What about the Arborvitae Nigra?
Our home is in Northern Virginia, in a neighborhood along the Potomac. This area of our co-joining yards has been graded so the drainage/water flows in a shallow ditch about two feet in from the property line (on our side). The area can get flash-flooding occasionally, and the ditch can get some temporary (24 hour) water logging. To alleviate water logging, we have created a mound that is ~24 inches tall. We have seen other Emerald barriers planted this way in our neighborhood that do really well... I just wish they were about 5' taller.
The distance from our home is only about 15-20', so we don't want to lose yard space (in addition to not going over the property line). The neighbor's house is only about 8-10' from the property line. I wish we had 30 or 40 feet to play with/reforest the area, but we don't.
1. Does any evergreen alternative exist that would get to 20' tall, but width of 5 or 6'?
2. Would it be weird/ugly to plant different types of evergreens interspersed with the Emeralds (in a row) to create some variation/height? (Our current plan is to keep the row of Emeralds and plant some other evergreen varieties in a few feet from the property line to add variation).
3. If we planted Nigra or some other Arborvitae/evergreen, would trimming to keep them within 5' be realistic and/or healthy for the tree?
4. How do Nigra or other arborvitae compare to the Emerald? Are there issues we should be aware of?
Hoping to order the trees now to get them in by the end of November-- appreciate your responses!