This is similar to my issue...a divided highway only 100 yards or so from the house. There's a narrow strip of a neighbor's land between, and she runs goats on it so no chance of dense buffer there. My edge is growing up pretty well in wild stuff, but it's mostly deciduous, and not very dense yet. So I'm gradually filling up the remaining space, currently an overgrown pasture, with everything fast, aggressive, and evergreen I can think of. Bamboo is near the top of my list....it will be confined by goats on one side, driveway on another, and my own mowing on the inside, so I'm fine if it fills up the rest. But it can kill back in the worst of our winters. I'm moving cedars and poplars out there too as I find them. I'd really like some Leyland cypress, if I could only find one nearby to get cuttings from. Got holly rooting, and privet likely to follow. For this purpose....a fast screen in a confined space, I'm after all the invasive, aggressive stuff I can get! Since I also burn wood for fuel and may well have sheep or goats of my own one day, the stuff will not fail for uses if it gets out of hand...