An Arborvitae turning brown is enough to send any well-meaning homeowner into a spin especially as these are seemingly steadfast evergreens. Most people know them for their festive allure, cheerful greenery, and undemanding nature and so observing discoloration and potential dryness can be a cause for concern.
In this article, I’m going to be covering the underlying issues you need to be aware of and how you can rectify them if you hit a rocky patch with your evergreens. I’ll also be explaining the additional steps you should take to prevent problems from reoccurring.
Read on to find the information you need to provide your arborvitae with the best possible care it deserves.
Reasons For Brown Arborvitae and How To Fix
If your arborvitae is turning brown, it is likely to be due to a lack of sufficient water or disease. This could be because of the following issues:
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Arborvitae Transplant Shock
When a tree is transplanted it may experience a certain amount of stress owing to possible damage to its root system. As a result, its leaves can begin to turn brown due to a reduced water intake.
Preventing Transplant Shock
To provide your transplanted arborvitae with the best chance of thriving in their new home, you should ensure the transplant hole is about three times as wide and as deep as the root ball.
You should also provide adequate amounts of water as well as a 3-inch layer of mulch which should surround the trunk but not be in contact with it.
According to Utah State University Forestry Extension, it is best to avoid fertilizing immediately — you will have to wait for a season or two after the transplant to do so.
It is worth noting it may take up to five years for your tree to fully recover from the ordeal.
Summer Drought
During summer the rate of transpiration of your tree will increase so that more moisture is exchanged with the atmosphere.
If your arborvitae is not provided with sufficient water, they will be unable to replenish the moisture drawn from their leaves into the hot air resulting in their turning brown.
Preventing Underwatering Issues in Summer
Providing adequate quantities of water and mulching will enable you to rectify the issue.
Winter Weather Burn
During winter your arborvitae might be at risk of reduced moisture due to freezing temperatures. It will also have to contend with harsh winds, frost, and the glare of the winter sun.
This can have a desiccating effect on the tree causing browning. The shock of transitioning from the heat provided by sunlight to the nighttime chill can also affect the cells of the tree and exacerbate the issue.
Preventing Winter Burn Patches on Evergreens
To ensure your arborvitae is ready for winter, water them during summer and fall, also provide a layer of mulching to provide insulation, taking care to leave a suitably sized gap between the trunk of the tree and the mulch. If possible, you should also wrap it in burlap.
Fungal Disease
If your arborvitae is distressed owing to adverse weather or climatic conditions, pests, or disease may strike.
Pestalotiopsis, one such adversary, prefers to get to work in the midst of dense foliage which is usually located towards the lower parts of the tree.
This fungal infection which prefers to attack during spring will inch its way from the tip of an arborvitae’s leaves toward its base creating a yellowing effect that will end up dark brown.
Treating and Preventing Evergreen Diseases
Affected parts of the plant should be pruned at once and your arborvitae should be regularly checked for any possible entry points that are most often caused as a result of damage due to heavy winds or storms.
Watering and fertilizing your tree will keep it in excellent health enabling it to stave off fungus and any other possible parasites.
Signs Of Arborvitae Turning Brown
The location of the affected part on your tree can be an indicator of just what is wrong with your arborvitae. Here’s a closer look at identifying problems that are localized.
Arborvitae Browning In Center
According to Iowa State University during colder weather, your arborvitae just like its other evergreen cousins may shed their foliage closest to the center since this is the oldest section of the tree which results in the evergreen browning near its center.
It is also the case, however, that more leaves than usual may be shed from the center of the tree if it happens to be stressed due to drought or disease.
Arborvitae Dying From Bottom Up
Root rot is one of the main culprits of this condition. The issue itself is caused by the presence of soggy soil due to poor soil conditions or overwatering which prevents roots from breathing.
As a result, fewer roots are available to provide the tree with the water and nutrients it requires to thrive and it will begin to brown from the bottom up.
This issue is best avoided by planting your tree in well-drained soil and avoiding overwatering. This will help to prevent the soil from becoming waterlogged.
Arborvitae Brown On One Side
This problem is most likely due to winter burns. Failing to adequately water your tree during summer and fall, and to take advantage of thawing to water your tree may contribute to it.
This is due to the fact that freezing temperatures can make it difficult for your arborvitae to obtain water from the soil. However, watering it before the onset of colder weather will make the soil damp, and therefore warmer, creating a more conducive environment for its roots.
It will also enable your tree to be able to store water in its tissues, roots, and leaves for when it needs them.
Mulch can also come in handy to prevent moisture from evaporating rapidly into the dry winter air.
Protecting your tree by wrapping it in burlap to protect it from the rigors of freezing weather can also be especially effective.
How To Save Brown Arborvitae Trees
There are a number of ways to tackle arborvitae that is turning brown and there are preventative methods to avoid the issue occurring in the first place.
Here are the most effective ways I’ve come across to save a troubled evergreen.
Pruning In Spring Or Summer
Pruning is not only ideal for training your tree to take on the form you desire it to but can also improve its health by eliminating diseased or broken branches.
When you prune your arborvitae in spring, you will provide it with the opportunity to sprout new foliage before the fall arrives.
Summer is another ideal time to prune since it will have time to recover and heal from any exposed cuts before the arrival of the fall.
Wrap Your Tree In Burlap In Winter
Burlap is the material of choice for protecting your evergreens from the extremes of winter and is a great way to avoid the damage caused by frost, snow, and extended periods of wet weather.
It will also keep hungry herbivores away that may otherwise cause damage to foliage, stems, branches, and trunks.
This woven fabric which is coarse in texture and sturdy in nature is commonly also used to wrap root balls to keep them in the best condition until they are delivered to their destination. It is not only breathable but durable too.
To safeguard your arborvitae before the onset of winter, simply place poles around the tree and wrap the burlap around them securely, fastening it down as you wrap.
Alternatively, you could wrap the arborvitae itself with the burlap starting from the top until you reach the bottom. Your tree should be cozily wrapped up, not swaddled.
The burlap will need to be attached with a clip and secured with twine. Fasten it at the apex, center, and base of your evergreens.
Water When The Ground Is Thawed
Even in winter dormancy, your Arborvitae still requires water however, in freezing weather conditions any water in the soil will become ice crystals that are unable to be absorbed by the tree’s roots.
To keep trees hydrated through winter when they are unable to absorb water, aim to water your trees deeply once or twice per month when you know the ground is frost-free. This will allow plant cells to retain a reserve of water and provide protection against the damage caused by plummeting conditions.
Water them in the morning and only when the temperature is above 40 degrees Fahrenheit. This will enable your arborvitae to take in the water it needs before temperatures drop in the evening.
Fertilizing Your Arborvitae
Bear in mind that Arborvitae have different fertilizing requirements depending on their age, how well they are performing, and the time of year. Here’s a rundown of what you need to consider.
Stage of Life and Age
Young or recently transplanted arborvitae trees should never be fertilized. New plantings are focusing on developing and establishing their roots. Fertilizing before the second or third year of maturity may lead to root burn and premature growth.
Overall Health and Vitality
Only healthy arborvitae will be able to put applied fertilizer to good use, especially when using a fast-acting feed.
If it happens to be in poor health, its condition may worsen as it uses its meager energy stores to push new growth.
I recommend using slow-release granules with a low-dose NPK ratio. This will allow nutrients to be introduced gradually and gently rather than all at once.
Time of Year
Like every other evergreen, your arborvitae should be fertilized in early spring. Doing so will provide it with the time it needs to sprout new growth during the summer growing season.
Type of Fertilizer To Use
When feeding in spring the best Arborvitae fertilizer are those with a higher proportion of nitrogen compared with ratios of phosphorus and potassium. Nitrogen helps with the production of new foliage and healthy root growth.
Using a fertilizer with added potassium and lower levels of nitrogen during the Fall will ensure your tree is equipped to handle the rigors of winter and prevent new foliage growth.
Popular Arborvitae Trees
Planting Arborvitae in your yard and garden can provide a host of benefits. From offering screening and privacy, providing protection against the elements to adding interest, texture, and depth of field to your landscape.
There really is an Evergreen for every occasion. Here are a few of my favorites.
Emerald Green Arborvitae
Stately and slender, this dwarf conifer is reminiscent of the majesty of country manors.
Known for its trademark dense foliage in a rich gem-like green, it is ideal for bestowing a touch of privacy on your surroundings as well as a hint of stately home elegance.
The tree which is referred to as Thuja Occidentalis by botanists is also referred to as the Eastern white cedar or Northern white cedar.
It is capable of reaching 15 feet in height and 4 feet in width and is especially noted for its drought resistance, cold tolerance, and ability to handle harsh winters.
The emerald green arborvitae prefers slightly acidic to neutral soil (with a pH of 6.8 – 7.2) and grows between hardiness zones 4 – 8.
It is generally low maintenance, and can withstand short snaps of frost but ideally needs at least 4 hours of sunlight daily to be able to maintain its thick foliage.
In addition, special care should be taken to water it regularly until it is 2 years old. After 2 years both pruning and fertilizing can take place.
Thuja Green Giant Arborvitae
This hybrid between the Japanese Arborvitae and the Western Red Cedar with its characteristic flat, frond-like leaves is actually of European origin.
The Thuja Green Giant Arborvitae (scientifically known as Thuja standishii × plicata) is known to turn slightly bronze in winter and is capable of reaching a height of 60 feet and a width of 20 feet.
It thrives in zones 4 – 7 and prefers soil that is slightly acidic to slightly alkaline within a pH range of 5 – 8.
The Thuja Green Giant prefers full sunshine and requires about 2 full hours daily. It will not tolerate deep shade, nor will it tolerate salt.
However, it is highly resistant to cold, heat, disease, and deer.
This fragrant conifer is also capable of growing pretty fast and can live for 40 years.
It is also low maintenance although it is susceptible to damage from strong winds.
Final Thoughts, Arborvitae Turning Brown
There are several factors that could result in your arborvitae turning brown. These include transplant shock, winter weather burn, and fungal disease.
Some of the most effective means of preventing these issues include effective watering, ensuring protection against weather extremes, and providing a slow-release, high-nitrogen fertilizer. Pruning at the right time and wrapping your trees in burlap can also prove helpful.
Overall, Arborvitae is relatively low maintenance and can enhance your landscape year after year. The tricks to keeping them in tip-top condition are simple and easy to get right, you just need to know what you’re doing and put the effort in from time to time. Then, it’s time to sit back and enjoy them.
