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Green Giant Arborvitae do turn brown in winter, and this natural color change is completely normal for this popular evergreen.
The reason your Green Giant Arborvitae turn brown in winter comes down to a fascinating survival mechanism that many evergreens share.
If you’ve spotted your trees taking on a bronze or brownish hue during the colder months, don’t panic.
In this post, we’ll break down exactly why Green Giant Arborvitae turn brown in winter, what other factors can cause browning, and when you should actually be worried.
Let’s jump in and take all the guesswork out of that winter color shift.
Why Green Giant Arborvitae Turn Brown In Winter
The main reason Green Giant Arborvitae turn brown in winter involves a process called photoperiodism and cold hardiness.
1. The Natural Winter Color Shift
Your Green Giant Arborvitae turning brown in winter is a physiological response to shorter days and colder temperatures.
As sunlight decreases, the tree’s chlorophyll production slows down.
Chlorophyll is the pigment that gives leaves and needles their vibrant green color.
When chlorophyll levels drop, other pigments like carotenoids become more visible.
These pigments create that bronze or brownish tint you see on your Green Giant Arborvitae in winter.
This shift actually protects the tree from winter damage.
The darker color allows the foliage to absorb more heat from the weak winter sun.
Over the last several decades, this has been the reason behind why Green Giant Arborvitae turn brown in winter so predictably.
2. The Tree Is Not Dying
When your Green Giant Arborvitae turn brown in winter, it can look alarming if you’re not expecting it.
But here’s the reassuring truth: this color change is temporary.
The tree is simply conserving energy and protecting itself from moisture loss.
Cold winds and frozen ground make it hard for evergreens to take up water.
The brownish color helps slow down transpiration, which is the loss of water through the leaves.
Your Green Giant Arborvitae turning brown in winter is actually a sign it’s adapting, not a sign it’s failing.
3. The Browning Is Usually Uniform
If you notice the browning happening evenly across the entire tree, it’s almost certainly the natural winter change.
The inner foliage closer to the trunk often stays a bit greener.
But the outer needles that face the wind and cold will take on that bronze look.
This uniform pattern is another clue that your Green Giant Arborvitae turning brown in winter is a healthy response.
Other Reasons Green Giant Arborvitae Turn Brown (And What To Do)
While the natural shift is the most common reason, there are other factors that can cause your Green Giant Arborvitae to turn brown in winter or at other times of year.
1. Winter Burn
Winter burn happens when the tree loses more moisture through its needles than it can take up from frozen soil.
Strong winds and bright winter sun can make this worse.
The symptoms usually show up on the side of the tree that faces the wind or the south and west where the sun is strongest.
To prevent winter burn, give your Green Giant Arborvitae a deep watering in late fall before the ground freezes.
You can also wrap young trees in burlap to create a windbreak.
2. Drought Stress
Even though they go semi-dormant, Green Giant Arborvitae still need water during dry winter spells.
If the soil is bone dry and the temperatures drop, drought stress can make the browning more intense.
This is why it’s so important to water your trees thoroughly in the fall.
Keep an eye on the soil moisture around your Green Giant Arborvitae turning brown in winter if you live in a region with dry winters.
3. Transplant Shock
Newly planted Green Giant Arborvitae are more likely to turn brown in winter simply because their root systems aren’t fully established.
A tree that was planted in the last year or two has a harder time taking up water from frozen ground.
Wrapping the tree or using an anti-desiccant spray can help reduce moisture loss.
Give your new trees a couple of winters to settle in, and you’ll see less dramatic browning.
When Browning Signals A Problem
Now you know the natural reasons why Green Giant Arborvitae turn brown in winter, but sometimes browning is a warning sign.
1. Pest Infestation
Spider mites and bagworms can cause browning that looks different from the winter color shift.
Pest damage usually appears as patchy brown spots rather than uniform bronzing.
Check for tiny webs or small bags hanging from the branches.
2. Root Rot
If your Green Giant Arborvitae are turning brown in summer or if the browning starts from the top down, root rot could be the culprit.
Poor drainage or overwatering causes the roots to suffocate.
Unlike the natural winter color change, this browning won’t reverse in spring.
3. Extreme Winter Injury
In harsh winters with sudden temperature drops, even established Green Giant Arborvitae can suffer serious damage.
If the browning is severe and the branches become brittle, the tree may have experienced dieback.
In most cases, the tree will push new growth in spring, but you may need to prune out the dead wood.
The key difference is that healthy winter browning is subtle and temporary.
Serious damage looks ragged, patchy, and much more severe.
So, Do Green Giant Arborvitae Turn Brown In Winter?
Green Giant Arborvitae do turn brown in winter, and in nearly all cases, it’s nothing to worry about.
This natural color change is a survival strategy that helps the tree get through cold, dry months.
The browning is usually uniform across the tree and reverses completely once spring warmth returns.
Just make sure you’re giving your trees enough water before the ground freezes and protecting younger plants from harsh winds.
With that simple care, your Green Giant Arborvitae turning brown in winter will be a temporary phase that adds a unique, seasonal texture to your landscape instead of a cause for concern.