Evergreen trees are usually the only thing green in our winter landscape. But when plagued by harsh weather or infestation in winter, the trees can be more brown than green.
While this can be an eyesore, it isn't normal and could be a serious problem. But does it mean the tree is dying from the top down? Or is the tree just in need of some TLC?
Four reasons why your evergreen is turning brown
• Winter weather — Evergreen roots rely on water stored in tree needles once the ground freezes. Winter drains the tree's water supply quickly, causing dryness and brown needles.
"The length of winter is what really causes them to dry out," said Gail Nozal, assistant district manager of S&S Tree and Horticulture Specialists based out of South St. Paul. "Water the trees as late as you can into the fall so that trees have a good moisture supply."
• Sunny days — Needles in direct sunlight turn uniformly brown and is an extra drain on the tree's resources in addition to winter elements.
"When a deciduous tree loses its leaves it basically shuts down — it doesn't transpire anymore," Nozal said. "Whereas evergreens continue to transpire (lose its moisture supply)."
• An infecting intruder — Evergreens attract a few common pests and diseases such as the pine beetle or cytospora canker.
"Pine bark beetles are very opportunistic during droughts," Nozal said. "Once the trees start to dry out, the beetles seek out those trees."
• It's just natural — Evergreens naturally wean out older needles as part of their growing cycle. When higher needles branch out, lower ones blocked from sunlight may die off.
"Trees go into a cycle every two to three years in which they drop their needles," Nozal said. "Evergreens grow at their tips so there is constantly needle loss."
Protective fixes for browning needles
• If the tree is suffering from dehydration try an anti-desiccant — a waxy coating sprayed on plants that helps shield them from moisture loss. Wait for temperatures between 40-50 degrees with no rain expected for 24 hours.
• If the tree is experiencing sunscald wrap bark in burlap to protect them from the elements.
• If the tree is infested with a pest call an arborist for a free consultation. In many cases an arborist can help your tree by either using an insecticide or pruning.
• If it's just natural ask your arborist if it's safe to prune brown branches for a better appearance.
If your evergreen is infected with cytospora canker, you may be wondering what that exactly means. According to the Davey Institute, the disease is predominantly found in blue spruce, Norway spruce, hemlock, red cedar, fir and white pine. The infection starts on the lower limbs and gradually works up the tree limb by limb. The disease itself is caused by a fungus, cytospora kunzei — a weak parasite that primarily attacks weakened trees. Drought, low fertility, mechanical injury, insect feeding or poor soil conditions make trees susceptible to Cytospora canker. There is no known cure for cytospora canker. If infected, good tree health will slow the disease's progress. During periods of drought, provide supplemental watering for landscaped trees. Remove infected branches, but be sure to sterilize pruning tools between cuts.