There are a lot of people, including landscapers, who plant trees too deeply. This almost always hurts the tree and is often fatal. This is easy to remedy if you know what to look for and how to plant correctly.
All trees need to be planted at the right depth for their roots, no matter what size or type of pot they come in. Read on and you can avoid one of the most common tree-planting mistakes.
Planting a tree too deep is one of the most common mistakes when installing new trees. It can lead to a host of issues from disease and pest problems to reduced growth and even death
Understanding the proper planting depth and technique is critical to get your new tree off to a healthy start In this guide, we’ll cover everything you need to know about how deep to plant a tree.
Why Proper Planting Depth Matters
Planting depth impacts a tree’s health because it determines the level of the root flare. The root flare, also called the trunk flare, is the part of the tree where the roots begin to flare out from the trunk.
This flare should always be at or slightly above the soil surface when planted. If buried too deep important trunk tissue can rot cutting off the passage of nutrients and water.
Trees planted too deeply are more prone to:
- Trunk and root rot
- Reduced growth
- Pest and disease problems
- Leaning and instability
- Premature decline and death
Ensuring the root flare is at the proper depth prevents these issues and sets up your tree for vigorous growth.
How to Determine the Root Flare Depth
Many nursery-grown trees are planted too deep in their containers or root balls. So you can’t simply dig a hole and install the tree at the same depth you receive it.
To find the correct depth, you need to locate the root flare first. Do this before digging the hole by:
- Carefully removing the tree from its container or burlap.
- Gently loosening and removing soil around the trunk until the first main roots are visible.
- Identifying where the trunk transitions into the root system – this is your root flare level.
The depth from the root flare to the bottom of the root ball is how deep you should plant the tree.
Digging the Proper Planting Hole
Now that you know the correct depth, dig a wide, bowl-shaped hole:
- Dig the hole only as deep as needed to plant at the root flare level.
- Make the hole 2-3 times wider than the root ball.
- Roughen and loosen the sides and bottom.
- Maintain a raised center “pedestal” of undisturbed soil in the center to prevent settling.
Proper hole sizing and shape allows for healthy root growth outward into the native soil.
Setting the Tree at the Right Level
When placing the tree into the prepared hole:
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Orient the tree with the best side facing out.
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Lift the tree by the root ball or container, not the trunk.
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Center in the hole, on top of the soil pedestal.
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Check that the root flare matches up with the surrounding grade.
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Set the tree in the hole with the root collar (area just above the roots) flush or slightly above natural grade. Planting too deep is a leading cause of mortality in newly planted trees.
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Don’t pick up the tree by the trunk once planted. Always handle by the root ball if repositioning is needed.
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Begin backfilling once the tree is positioned correctly.
Backfilling and Watering In
Follow these steps when backfilling the hole and watering:
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Backfill about halfway with the soil previously removed. Pack down gently with your foot to stabilize.
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Fill the remainder of the hole, still lightly tamping to prevent settling. Do not tamp heavily or over-compact.
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Build a shallow berm outside the planting area to help retain water.
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Water thoroughly until the entire root ball and surrounding soil is fully moistened.
Proper watering at planting time is critical. Monitor that the tree does not settle too deeply into the hole after watering.
Providing Support
In windy areas or for top-heavy trees, staking provides added support after planting:
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Use wide nylon or canvas straps to prevent bark damage.
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Allow for some trunk movement and flexing. Don’t immobilize the trunk completely.
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Remove stakes after the first year once the root system establishes.
If staking is not needed, skip this step. Allowing the trunk to sway slightly in the wind encourages proper trunk taper and strength.
Following Up After Planting
Post-planting care ensures your tree thrives:
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Water deeply and regularly for the first two years, tapering off as the tree establishes.
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Apply 2-4 inches of organic mulch over the root zone, avoiding contact with the trunk.
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Monitor for signs of problems like pests, diseases, or nutrient deficiencies.
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Only prune sparingly and when necessary during early years.
With proper planting depth and follow-up care, your tree will quickly establish and grow vigorously for years to come. Avoiding the pitfalls of deep planting gives your tree its best start.
Common Questions About Tree Planting Depth
Proper planting techniques ensure you avoid some of the most common tree failures. Here are answers to some frequently asked questions:
How deep should the hole be to plant a tree?
Dig the hole only as deep as needed to accommodate the root ball with the root flare at grade level based on your soil evaluation. Generally 12-18 inches for smaller nursery-grown trees.
Should the root flare be above or below ground when planting trees?
The root flare should be right at ground level or no more than 1-2 inches above the surrounding soil. Never below.
Is it okay if my tree planting hole is deeper than needed?
No. If over-dug, backfill with additional soil until at the proper depth matching the root flare level.
Can planting too shallowly damage trees?
Yes. Planting too high exposes roots and dries them out. Aim to have the flare match the grade. If unsure, too high is better than too deep.
How much soil do I remove when finding the root flare?
Remove only as much soil as needed to identify the first main roots emerging from the trunk and note this depth. Do not over-expose the roots.
Following proper planting technique tailored to each individual tree is vital to prevent planting depth problems. Ensuring the root flare is at the correct level avoids issues and gets your tree off to its best start. With this guide, you’ll know exactly how deep to plant your tree.
WATERING YOUR NEW TREE
In dry, hot places, it’s always a good idea to add a rounded lip or berm to the backfilled soil just outside of the rootball. This makes a shallow dish-shaped center around the rootball that will hold water while it seeps into the ground. Providing enough water to new trees is important, as it prevents damage to your tree from heat stress.
Place plants and build a berm. Then, put the end of a garden hose in the depression and turn on the water to a slow trickle. You don’t want a steady flow of water that could wash away soil and expose roots. Instead, you want a slow watering that soaks into the rootball and the soil around it. Leave the water to trickle in for several hours, checking periodically that water is being readily absorbed. When you water, the backfilled soil may sink below the rootball. Fill in the holes with new soil until it’s level with the top of the rootball.
Add a 3” layer of mulch from the berm outwards, with a 2-3’ diameter. Mulch is vital to help hold water in the soil, regulate soil temperature, and to suppress weed growth. Remember to add more organic mulch every so often because it breaks down in the soil, and make the mulch ring bigger as the tree’s crown (and root system) grows.
WHEN YOU NEED HELP PLANTING A TREE
The information above applies to all trees – planting too deep is a leading cause of tree death. But it’s only practical for a homeowner to plant smaller trees. Professional tree care workers with the right tools and knowledge should plant bigger trees, even ones that come in planting boxes that are 24 inches or bigger.
Give us a call if you’d like to plant a larger tree on your property. We can recommend the best options, select and deliver the tree, and then plant it properly.