In winter, people in the Hamptons know how to protect the things they value. The decorative hedges outside multimillion-dollar homes are carefully wrapped in burlap. Bolts of cloth are unspooled, cut and pulled taut. Then they’re stitched closed by hand with specialized needles, sold in local shops. That’s because the cold is potentially deadly to some of these plants — when the water inside them freezes, it expands, rupturing the cell walls.