Evergreens, such as Arizona cypress, cedar, juniper, ligustrum, may suffer winter injury when inadequate moisture is available or when soil temperatures are considerable below air temperatures. Although these plants do not transpire as much water in the winter as they do in the summer, they still remain active and thus may need additional water in the winter months. When soils are cold and warm dry winds blow, roots cannot take up enough water to balance the loss through the leaves. Yellowing and browning of the foliage and even death may occur. These conditions are most likely to exist in late winter or early spring.
Evergreens suffer less damage if protected by wind breaks.
Some plant species have a lower tolerance to cold temperature than others. Before purchasing landscape plants, obtain information regarding winter hardiness. In many areas of the state, azalea, boxwood, ligustrum, oleander, pyracantha, pittosporum, fig, crapemyrtle and hibiscus may be damaged during cold winters. Injury may consist of only a few tips or branches dying back. When this is the case, judicious pruning will improve the looks and balance the top growth but it should be done after the exact dead areas are determined.