With their habit of remaining verdant and cheerful through fall and winter, Evergreens have the added advantage of being able to provide a hint of green magic through those cold and sometimes uninteresting months.
Hence, it’s hardly any surprise that any appearance of browning can mar that fairytale allure and become a cause for worry. And as someone who loves greenery, I can attest to what doing your very best to get that lush foliage back, feels like.
And that’s why I will be taking a close look at the key causes of an evergreen turning brown, and how to resolve the issue so you can provide your evergreens with the care they deserve.
- Pruning In Spring Or Summer
- Wrap Your Tree In Burlap In Winter
- Water When The Ground Is Thawed
- Fertilizing Your Evergreen
Causes of Evergreens Turning Brown
There are several reasons your evergreen might be turning brown, ranging from insufficient water intake to disease and shock. Here’s a closer look at those common issues:
Transplanting trees will put them at risk of stress as a result of the procedure.
This is often due to damage to the roots resulting in a reduction in a tree’s nutrient and water intake.
It may take up to five years for a tree to recover fully from transplant shock. This image shows two Arborvitae browning due to transplant show and the third central tree suffering mild shock with lower branches browning.
High temperatures can adversely affect trees, evergreens included. The strain of handling all that summer heat and the resulting heated soil can bring about increased transpiration i.e., the arboreal equivalent of sweating.
In time the imbalance between the moisture in the atmosphere and that contained in a tree’s leaves results in their drying.
This condition often also causes browning to the smaller outer branches and twigs of evergreen as well.
Winter Weather Burn
A common problem that affects evergreens of all varieties is winter weather burn. The problem here is that the issue doesn’t quite make itself known until spring when the full extent of its damage can be seen. This condition is caused when a tree is unable to replace transpired moisture owing to frozen soil and harsh winds.
As a result, dehydration spreads inwards from the leaves turning parts of the tree brown. Although certain trees may recover from it, there are those which do not owe to the condition is widespread throughout the plant.
Trees which have poorly developed root systems are especially susceptible to this issue.
Those who have experienced late summers may also fall foul of winter weather burn. This is when the persistence of warm temperatures prevents the tree in question from slowing down its metabolic processes with the coming of the fall. In many cases, the evergreen will produce new buds, only to be burned by the onset of plummeting winter conditions.
One of the most common causes of fungal infections in evergreens is Phytophthora which according to Utah State University Extension, is a water mold with a preference for drenched, warm areas.
Symptoms include reddening or browning of leaves as well as discolored roots, and once they have become noticeable, the infection is likely to have established itself in the root system.
The condition can be treated by draining the soil and preventing the fungus from thriving.
Symptoms Of Brown Evergreen Trees
Browning in evergreen trees can take different forms and quite often, these varying instances are caused by different issues as well. These include:
Browning From The Center
In several instances, the main cause of a tree drying from the inside out is root rot. The browning from the inside out tells you that the plant is doing its best to remain alive despite struggling with a compromised root system.
The best course of action is drying the ground and refraining from watering until it is no longer drenched with excess moisture.
Depending on the size of the evergreen and the extent to which roots may be accessible, it is highly beneficial to snip off infected roots to cease any further spread of disease.
Dying From The Bottom Up
If your cedars or pines happen to be affected by this condition, there are likely to be several underlying factors including disease, pests, or simply drought. Here’s a closer look at those factors:
In this first instance, CytoSport canker is often one of the main culprits. The disease which mainly infects malnourished or diseased plants tends to mostly affect red cedar, white pine, and blue spruce.
According to the University of Minnesota Extension, the infection is caused by the fungus Leucostoma kunzei which lies dormant in healthy trees only to manifest following distress due to insect infestation or drought.
The main means of resolving the issue is by providing your trees with enough water and nutrients to enable them to keep the infection at bay. It is also important to inspect your trees every 12 months and to remove any infected branches.
The disease will reveal itself by the presence of resin-filled blisters and dark bumps which contain yellow spores that can spread to other branches through the air.
Bark beetles are some of the most common pests which love to infect evergreen trees, including pines.
These arthropods which possess an uncanny ability to spot weakened trees flock to selected pines in their numbers.
They consist of more than just one species and include black turpentine beetles, IPS beetles, and southern pine bark beetles which each prefer the lower, middle, and upper portions of a tree respectively.
Their modus operandi is pretty similar: they simply burrow beneath the bark and reproduce copiously.
The presence of dust close to holes or larva and adults beneath bark are a clear sign that you’re dealing with an infected tree.
Limiting drought conditions, mulching, and watering can ensure your trees are healthy enough to keep bark beetles away. Thinning to prevent excessive competition for limited resources between trees is also recommended, as is removing infected trees to limit the spread of the infestation.
Insufficient quantities of water could cause your tree to focus its care and attention on higher needles to conserve moisture. Those on its lower part thus neglected, desiccate, and are shed.
Ensuring you provide your evergreen with enough water, particularly during warmer months and winter could ensure it has enough moisture to go around.
Patches of Brown on Evergreens
Quite frequently this issue is caused by winter sunscald. This condition arises during the coldest season of the year when one part of the evergreen is exposed to harsh elements including wind and sunshine.
When freezing winter temperatures strike at nightfall following daytime sunlight, the sharp, sudden change kills the cells residing in the phloem and cambium layers.
A lack of sufficient water may also play a role in trees turning brown in this manner and is often noticeable by the presence of cracks in the bark.
Tree wraps are one of the most common means of combating the condition as are corrugated tree guards.
How To Save Brown Evergreen Trees
If your cedars, junipers, pines, or any other evergreen species for that matter, are turning brown there are steps you can take to save them. The following are some of the most common and efficient options for doing so:
Pruning In Spring Or Summer
Pruning diseased or broken branches can prevent infection from spreading throughout the tree and from possibly affecting its neighbors. Early spring which is the period of new growth is the best time for this exercise.
Summer is also another excellent period during which you can prune them since they become semi-dormant during the warmest months of the year.
The fact that new growth will have expanded by spring and summer also makes these seasons ideal periods for pruning.
Wrap Your Tree In Burlap In Winter
It may sound counterintuitive but covering your evergreen during the winter months with burlap is great for regulating tree temperatures and can help to deflect harsh winter sunlight thanks to its light color. Burlap is woven from hemp or jute fibers and is naturally white or pale brown in color.
Burlap is also breathable ensuring air will be able to circulate around the tree, unlike plastic which will let nothing in or out.
When used to wrap your evergreen trees, burlap can provide protection from harsh winter winds, sharp fluctuations in temperature, and even hungry herbivores in search of dinner.
I prefer to drive stakes into the ground around my evergreen trees (they need to be higher than the plant) and wrap the burlap around them before fastening it. This forms an open-top column.
Alternatively, you could wrap the fabric around the tree ensuring some space is left between its apex and the material which should then be fastened above it, in the middle, and at the base using twine.
I wait until the final threat of frost has passed, before unwrapping my trees.
Water When The Ground Is Thawed
The dryness of winter can put your evergreens at risk of dehydration and drought stress.
Providing them with water when the ground thaws will place them in a better position to handle the rigors of the season. In any case, temperatures must be higher than 40° Fahrenheit before watering.
Watering your trees adequately in the fall will also ensure they’re better equipped to face the arrival of winter. Thanks to their sufficient stores of water, they will be able to make up for the loss of moisture through their leaves.
Fertilizing Your Evergreen
Timing is one of the most important factors you will have to keep in mind when using fertilizer for evergreens.
Evergreens need sufficient time to absorb the nutrients from fertilizer, so starting in early spring and using a slow-release feed is the best option for the exercise.
Applying evergreen fertilizers later than mid-summer, i.e., around July is inadvisable due to the fact that doing so would encourage new growth which would be vulnerable to the harsh winter cold.
You should also avoid fertilizing trees that happen to be distressed. Doing so will compel them to push for new growth which they will be ill-equipped for, stressing them further.
It is worth noting that evergreens generally thrive in acidic soil. Hence carrying out a soil test is recommended to ensure it is the right pH to enable your trees to absorb nutrients efficiently and at the correct ratios of macronutrients.
In terms of the NPK ratio, it is best to select a high nitrogen fertilizer. This nutrient is not only the easiest for your evergreens to take in but will also encourage healthy foliage and help to maintain a lush green color year-round.
Popular Evergreen Trees
Emerald Green Evergreen
Native to Canada, this tree is also referred to as Emerald Green Arborvitae (i.e., tree of life).
Best grown in hardiness zones 3 – 7, it is recognizable by its slender conical form and its dark green scaly leaves which have a mild fragrance and maintain their verdant luster in winter.
This variety of cypress is capable of growing to heights of 20 feet and providing a spread of 4 square feet, and generally has a lifespan of three decades although it can live for much longer (up to 120 years).
It has a preference for well-drained soil with a pH ranging between 6 – 8.
Despite preferring cooler temperatures, it is capable of handling six hours of sunlight daily. However, it will not tolerate the extremes of total shade or excessive sunshine and warmth.
Thuja Green Giant Evergreen
A cross between the western red cedar and the Japanese arborvitae, this evergreen actually has European origins.
Capable of being grown in hardiness zones 5 – 8, its main characteristics are its dark green leaves spread out in a beautiful fan-shaped arrangement.
The Thuja Green Giant is capable of reaching 60 feet in height and living for decades. Like the Emerald Green Arborvitae, it prefers soil with a pH range of 6 – 8.
It is shade resistant although it prefers sunny weather and is also resistant to disease, deer, and drought.
Final Thoughts, Evergreens Turning Brown
Although evergreens are renowned for their ability to maintain their verdant foliage throughout winter, there are a number of reasons why they may turn brown.
These include winter weather burns, fungal diseases, or water issues.
Providing them with fertilizer when necessary and watering them before and during winter can provide them with the resources they need to withstand adverse weather and environmental conditions, as can providing them with a protective burlap covering where required.