I'm looking for a low maintenance evergreen shrub to plant over my water well, without risking damage to the well by plant roots. The water well comes up into a 10' long x 3' wide x 3' tall natural stone raised flower bed bordering my neighbour. Currently there are perennial flowers in there, but I would prefer to plant some kind of evergreen shrub to create privacy. It only has to be 4-5' tall since the flowerbed is already 3' off the ground.
I'm considering some kind of juniper or boxwood. If that's not safe, I'm thinking corn, or perennial grasses. Anything tall and dense will do.

I'm in orange county new york state zone 6 and the spot is fairly sunny.

Nowadays, small Hollies are frequent in New York City's woodlands, especially near shorelines, where the plants find suitably well-drained soils.