Why Are My Conifers Turning Brown?

One day your beautiful conifer tree was lush and green, then the next day you noticed it was turning brown. What happened so quickly to turn the needles of the conifer brown?

It’s shocking to see the once healthy green evergreen draped in brown needles and looking sickly. There are a few potential causes behind the browning needles, read over them so you can discover the cause, and hopefully the cure, as to why your conifers are turning brown.

Winter Drying

This is the most common reason that conifers turn brown, especially if it occurs during the winter.

Conifers lose moisture through their needles in winter, causing them to dehydrate. This is normal and will not cause the tree any long-term damage. The lost water through the needles and the frozen, dry soil that does not provide moisture to the tree roots results in a few needles turning brown.

Examine the needles closely. If the end of the brown needles nearest to the branch remain green,the conifer will recover when the weather warms up. Sometimes the damage is more severe and entire branches turn brown and will need to be removed but the tree will recover.

Conifers will recover from winter drying as soon as the soil thaws and the trees receive water.

Prevent winter drying by planting conifers that are native to your climate. Plant them in an location of your landscape that is protected from winds, like on the south side of a structure.

Water young conifers regularly throughout the fall and winter if ground is not frozen. Add a 6-inch layer of organic mulch around the tree help prevent roots from freezing.

Over-Pruning

If it’s not winter and your conifers are turning brown, think back to the last time you pruned them. Over-pruning or pruning at the wrong time of year can cause the evergreens to turn brown.

Pruning on a hot day, during a drought when the evergreen is already stressed, or in the fall/autumn can cause conifers to turn brown.

To prevent over-pruning conifers, lightly prune them 2-3 times between April and August. If using a long reach hedge trimmer  or pruner try not to take too much off in one go.

Diseases

Conifers are prone to viral, fungal, and bacterial diseases, any of which can cause the evergreens to turn brown. Conifer diseases can strike at the needles, the roots, the trunk, and/or the branches.

If a disease is suspected, prune off diseased portion and apply a fungicide, herbicide, or other treatment to prevent the disease from spreading to healthy branches.

If a conifer is crowded and air-circulation is impeded, removing the nearby plants will also improve the health of the conifer.

* Needle Cast disease will cause the needles to first turn yellow, then brown and fall off. To stop the spread of this conifer disease, remove all infected needles and apply a fungicide all over the tree.

* Spruce Needle Rust only affects spruce trees causing branch tips to turn yellow. Bright orange and white nodules show up on infected needles that release orange spores into the air. Prune off diseased branches and treat conifers with a fungicide.

Insect Infestation

Several insects enjoy the flavor of conifers and will eat away at them until the evergreen is dead. Observation and fast treatment with an insecticide will kill the insects and save your conifers.

* Pine needle scale will cause needles to turn yellow, then brown, and eventually fall off. Trees infested with pine needle scale have few needles and branches begin to turn brown. If left untreated, pine needles scale will kill the conifer.

* Cyprus Aphids are one of the most common insects that attack conifers. Brown patches start to appear on the evergreen along with sooty-looking mold topped with a sugary honeydew secreted by the aphids.

Cyprus aphids will suck all the sap out of conifer needles and be gone before the needles turn brown. Observe evergreens and treat with a pesticide if you notice any of these aphids on them.

* Spruce Spider Mite appears in the cool weather of spring and fall/autumn. Spruce Spider Mites are easy to recognise and easy to get rid of – these insects leave behind silk threads on the needles of the conifer they have infested. Spray with an insecticide in spring and fall/autumn to prevent them from infesting your conifers.

* Pine Mountain Beetles lay their eggs in spaces between the trunk and the tree bark . The beetles leave behind a fungus when they deposit their eggs that prevents the conifers from up taking water and nutrients. The tree remains green and looks healthy when the eggs are first laid but the needles will soon turn brown and the tree will die within one year.

Act Quickly

Observation is key to early detection of any problems your conifers may be having. Do what you can to prevent diseases and pest infestation that can cause conifers to turn brown, and act quickly if you notice any problems so the evergreen can regain its’ health and beauty.