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Green giant arborvitae should be planted so the root ball’s top is level with or slightly above the surrounding soil, never deeper.
Getting this depth right is one of the most important steps when you plant green giant arborvitae.
If you plant too deep, the roots suffocate and the tree struggles or dies.
If you plant too shallow, the roots dry out and the tree can’t anchor properly.
So how deep do you actually need to dig?
In this post we’ll walk you through exactly how deep to plant green giant arborvitae, why depth matters so much, and what happens if you get it wrong.
Let’s dig in.
How Deep to Plant Green Giant Arborvitae – The Simple Rule
The golden rule for how deep to plant green giant arborvitae is simple: plant it at the same depth it was growing in its nursery pot or burlap ball.
Never bury the trunk flare or pile soil up against the stem.
Here’s why that rule is so critical and how to apply it correctly.
1. Find the Root Flare First
Before you start digging, look for the spot where the topmost roots meet the trunk.
That’s the root flare, and it should sit right at soil level after planting.
If you can’t see the root flare because the nursery pot is packed too deep, gently brush away some soil until you find it.
This flare is your visual guide for how deep to plant green giant arborvitae.
When you place the tree in the hole, the flare should be even with or an inch above the surrounding ground.
2. Measure the Root Ball Height
Another reliable method is to measure the height of the root ball itself.
The hole you dig should be exactly as deep as the root ball is tall.
If the root ball is 12 inches tall, dig a hole 12 inches deep.
Do not dig deeper thinking the soil will settle – that’s a common mistake that leads to planting green giant arborvitae too deep.
Instead, dig the hole to the exact root ball height and then widen it to about 2 to 3 times the width of the root ball.
This encourages roots to spread outward rather than staying in a narrow hole.
3. Adjust for Soil Type
Your soil type can slightly affect how deep to plant green giant arborvitae.
In heavy clay soil, it’s safer to plant a bit higher – about 1 to 2 inches above ground level – so the root ball doesn’t sit in water.
In sandy soil, you can plant exactly level because water drains quickly.
In both cases, the key is never to plant lower than the root ball’s original depth.
If you’re unsure, always err on the side of planting a little high rather than too deep.
Common Mistakes When Planting Green Giant Arborvitae Too Deep
Planting green giant arborvitae too deep is the number one killer of newly installed trees and shrubs.
Here are the three main problems that happen when you bury the root flare.
1. Root Suffocation and Rot
When you plant green giant arborvitae too deep, the roots are starved of oxygen.
Soil above the root ball traps moisture and prevents air exchange.
Over time, the roots begin to rot, and the tree shows signs of stress like yellowing needles, stunted growth, or sudden browning.
Once root rot takes hold, it’s almost always fatal.
2. Girdling Roots
If the hole is too deep and the roots are forced into a tight circle, they can start wrapping around the stem.
These girdling roots eventually cut off the tree’s nutrient and water flow.
You might not notice the problem for a year or two, but by then the damage is done.
Proper depth prevents roots from circling and encourages them to spread outward.
3. Weak Anchoring
A tree planted too deep often develops a weak root system near the surface.
The deeper roots don’t get enough air, so the tree relies on shallow, unstable roots instead.
This makes the arborvitae more likely to lean or topple in strong winds.
Getting the depth right from day one gives the tree a strong, stable foundation.
Step-by-Step Guide to Planting Green Giant Arborvitae at the Right Depth
Now you know why depth matters, here’s a simple step-by-step to guarantee you plant green giant arborvitae correctly.
Step 1: Prepare the Hole
Dig a shallow, wide hole that matches the root ball’s height but is 2 to 3 times wider.
For example, if the root ball is 12 inches tall and 10 inches wide, dig a hole 12 inches deep and 20 to 30 inches wide.
Place the excavated soil on a tarp so you can easily refill later.
Step 2: Set the Tree in the Hole
Lower the green giant arborvitae into the hole gently.
Check the depth by placing a stick or a shovel handle across the hole.
The top of the root ball should be level with that stick.
If it’s too high, scoop out a little more soil.
If it’s too low, lift the tree and add some soil beneath the root ball.
Never pull the tree up by its trunk; always lift the root ball itself.
Step 3: Backfill and Water
Once the depth is perfect, start backfilling with the original soil.
Do not add amendments like compost or fertilizer directly into the hole – this can discourage roots from spreading into native soil.
Gently tamp the soil as you fill to remove air pockets, but don’t pack it so hard that water can’t drain.
After backfilling, water thoroughly to settle the soil.
Add a 2 to 3 inch layer of mulch around the tree, but keep mulch away from the trunk to prevent moisture buildup.
So, How Deep to Plant Green Giant Arborvitae?
How deep to plant green giant arborvitae is straightforward: at the same depth it was in its container, with the root flare visible at or slightly above ground level.
Never bury the trunk or dig a hole deeper than the root ball.
A wide, shallow hole gives the roots room to spread, while the correct depth prevents rot, girdling, and instability.
Follow the steps above and your green giant arborvitae will thrive for decades.
Happy planting.