You'd think young arborvitae would retain their pyramidal, columnar, or conical shape as they grow, but they love to spread out and gain height as they mature, crowding the space.
While this works well as a hedge or privacy screen, it can result in immense property damage when the fragrant, needle-like leaves brush against your home's roof and walls.
Plus, most cultivars grow pretty tall and, unless pruned regularly, pose a massive risk if placed underneath power lines, gutters, or overhanging roofs.
Moreover, if standing close to windows, their grown canopies block all scenery, and the spindly leaves can retain water and stimulate mold and mildew growth along the wall siding.