Leyland cypress (x Cupressocyparis leylandii) has a lot going for it. It’s fast-growing with evergreen, feathery foliage and a pleasing, slender profile. It makes an excellent specimen tree or screening plant. A cross between two Pacific coast species, the Leyland cypress thrives best in moist, cool climates with moderate temperatures. These trees are hardy to zone 6, however, they do not tolerate sudden temperature fluctuations. We indeed experienced some of these very cold sudden temperature fluctuations this past December and January. The first winter damage symptoms will begin showing up as browning and dieback this spring as temperatures begin to warm and stimulate new growth.