Though evergreen trees keep their colour throughout the year, they often start to turn brown because of pathogenic disorders or poor cultural management. Discolouration of evergreens starts from the needles and spreads throughout the branches and whole tree.
Browning evergreen disorder usually is referred to as needle blight. The problem is common in arbor vitae, juniper and yew trees. Symptoms of needle blight are more pronounced on pine and spruce trees.
Insufficiently irrigated trees are highly prone to the disorder and start to brown because of drought. Poorly watered trees also become susceptible to winter damage that causes browning. Root rots caused by fungal infections are among the pathogenic reasons for brown needles and branches. Evergreens growing at higher elevations are more likely to suffer root rot.
Initial signs include needle discolouration, where large numbers of needles start to turn yellow, purple or red, eventually turning brown. Discolouration starts from the top, and soon entire branches and the tree assume a brown look. If disorder is not corrected in time, the affected tree dies within a couple of seasons.
Water trees adequately, as this protects them from drought. Sufficient irrigation is especially important during warm weather. Apply mulch to retain moisture in roots. Avoid over-watering, as this promotes fungal growth that causes root rot. Feed trees in spring with a balanced fertiliser.