Winters in the Northeast can wreak havoc on broadleaf evergreens like rhododendron, holly and boxwood. Drying winter winds and sun pulls moisture from leaves, and because the ground is frozen, plants can't recover the water loss through roots. Stressed leaves can then shrivel and turn brown.
WILT STOP and WILT-PRUF are two natural antidessicants that protect leaves from excessive moisture loss. The products are derived from pine tree resin. Simply spray the upper and lower surfaces when the leaves are dry (and there is no rain in the forecast for a few days). Do this when the temperatures are above freezing, ideally in the 40s or 50s.
In colder regions, apply this clear, protective coating twice: once in late November or early December and again in February by following the application directions. These products can also be used on some conifers BUT not blue-needled plants (these already have a natural waxy coating). The spray can also help protect plants from salt damage along roadways.
Antidessicants can also be sprayed on evergreen boughs, wreaths and cut Christmas trees to reduce moisture loss and help them last longer.