Will Arborvitae Grow Near Black Walnut Trees

Arborvitae will not grow well near black walnut trees because black walnuts produce a toxic chemical called juglone that harms many plants.
 
If you’ve been asking yourself, “will arborvitae grow near black walnut trees,” the short answer is no, and it’s not just a matter of a little extra care.
 
Juglone is released from the roots, bark, leaves, and nut hulls of black walnut trees, and it can poison sensitive plants like arborvitae.
 
In this post, we’ll explore why arborvitae struggle near black walnut trees, what juglone does to them, and whether there’s any way to make this pairing work.
 
Let’s dig in.
 

Why Arborvitae Won’t Grow Near Black Walnut Trees

Arborvitae will not grow near black walnut trees, and here’s why:
 

1. Juglone Is Toxic to Arborvitae

The main reason arborvitae won’t grow near black walnut trees is juglone, a natural chemical that black walnut trees produce.
 
Juglone is allelopathic, meaning it suppresses competing plants.
 
For arborvitae, juglone is outright toxic.
 
It damages the roots, disrupts nutrient uptake, and causes the tree to decline slowly.
 
You’ll often see wilting, yellowing, and stunted growth before the arborvitae eventually dies.
 

2. The Root Zone Extends Far Beyond the Canopy

Many gardeners assume that arborvitae will grow near black walnut trees if planted outside the drip line.
 
Unfortunately, that’s not true.
 
Black walnut roots can extend two to three times the width of the canopy.
 
That means juglone can be present in the soil far beyond where you’d expect.
 
So even if you plant arborvitae several feet away from a black walnut tree, the roots may still reach it.
 

3. Rain Spreads Juglone Through the Soil

Rain makes the problem worse.
 
When it rains, juglone leaches from leaves and nut hulls into the soil.
 
This creates a toxic zone around the black walnut tree that can persist for years.
 
Arborvitae planted in that zone will struggle no matter how well you care for them.
 

4. Arborvitae Are Highly Sensitive

Not all plants are equally affected by juglone.
 
Some trees and shrubs tolerate it, but arborvitae are not one of them.
 
They’re considered highly sensitive to juglone, which means even small amounts can cause serious damage.
 
If you’re wondering whether arborvitae will grow near black walnut trees, the answer is a firm no for this reason alone.
 

Signs Arborvitae Are Suffering From Juglone Toxicity

If you already have arborvitae near a black walnut tree, watch for these signs:
 

1. Yellowing or Browning Foliage

One of the first signs is yellowing or browning of the needles.
 
This happens because juglone interferes with the plant’s ability to take up water and nutrients.
 
The discoloration usually starts at the tips and works its way inward.
 

2. Stunted Growth

Arborvitae near black walnut trees often stop growing altogether.
 
New growth may be sparse or absent.
 
Over time, the tree becomes smaller and weaker compared to healthy arborvitae elsewhere in your yard.
 

3. Wilting Despite Adequate Water

Even if you water regularly, arborvitae affected by juglone will wilt.
 
That’s because the toxin damages the roots, making it impossible for them to absorb moisture properly.
 
This can be confusing for gardeners who assume the problem is drought.
 

4. Branch Dieback and Eventual Death

As toxicity progresses, branches begin to die back.
 
The arborvitae may lose large sections of foliage.
 
Eventually, the entire tree dies, often within a few years of planting near a black walnut.
 

Can You Make Arborvitae Grow Near Black Walnut Trees?

In most cases, no.
 
Arborvitae will not grow near black walnut trees, even with extra watering, fertilizer, or soil amendments.
 
Juglone persists in the soil and continues to harm sensitive plants.
 
You could try planting arborvitae in a raised bed with a barrier to keep walnut roots out.
 
But keep in mind that walnut roots can travel far and may eventually find their way in.
 
If you really want arborvitae, plant them well away from any black walnut trees.
 
A safe distance is usually at least 50 feet beyond the canopy’s drip line, though more is better.
 

So, Will Arborvitae Grow Near Black Walnut Trees?

Arborvitae will not grow near black walnut trees because of juglone toxicity.
 
This chemical is released from the roots, leaves, and nuts of black walnut trees.
 
It damages arborvitae roots, causes yellowing, stunting, and eventual death.
 
If you want healthy arborvitae, plant them far away from black walnuts.
 
And if you already have arborvitae near a black walnut, unfortunately, the best move is to relocate them before it’s too late.
 
Now you know exactly whether arborvitae will grow near black walnut trees.