Tree Planting
the natural way
Illustration of how trees should be planted.
Closer detail of the bottom of the tree planting illustration
This is the first in a series of newsletters that should help explain my tree planting information in more detail than ever before.
1. DIGGING THE HOLE
The first step is to dig the hole the correct size and shape. Before starting to dig the hole, the actual height of the root ball needs to be established. Most trees, in containers and balled and burlapped, have excess soil on the top of the true root ball – even under the burlap so removing the burlap at least on top of balled and burlapped trees is important. Then you can measure the true height of the root ball. Excess soil needs to be removed. Now you can measure the width and the height of the actual root ball.
Dig a wide, rough-sided or square hole, 2 to 3 times wider than the tree ball, especially at the soil surface. The width of the bottom of the hole isn’t as important. The point is to have well aerated soil around the new root ball and to prevent the roots from circling in the hole.
Digging a small, smooth-sided hole is the worst thing you can do. The depth of the hole should be slightly less than the height of the ball. Measure – don’t guess. Dig the hole a little less than the vertical height as explained in the last newsletter. Most trees are planted too deeply in the ground. The root flare is part of the trunk, not part of the root system and should be placed above ground.
The worst way to dig a tree hole – small and round.
Holes dug with augers are worse than those dug with shovels
The top of the root ball should be slightly higher to allow for settling. The bottom of the root ball should be sitting on firm undisturbed soil. Over-digging and putting backfill under the ball can allow the tree to settle. THIS IS A COMMON CAUSE OF ROOT FLARES BEING TOO DEEP IN THE GROUND. If fill under the ball is unavoidable, tamp to compact and set trees and other woody plants at least an inch higher than ground grade.
One of the results of planting in a small, smooth-sided hole.
2. PERK TEST
A percolation test, or perk test, is a way to evaluate the absorption rate and/or drainage of the soil.
When time allows after digging the hole and before the tree is planted, fill the hole with water and wait until the next day. If the water level does not substantially drain away overnight, a drainage problem that would negatively affect most trees is indicated. For wet soil-adapted trees like bald cypress and willows, this procedure isn’t necessary.
If drainage shows to be an issue, the tree needs to be moved to another location or have drainage added in the form of a PVC drain line set in gravel running from the bottom of the hole to a lower point on the site. Another draining method that sometimes works is a pier hole dug down from the bottom of the hole into a different soil type and filled with lava gravel. A sump from the top of the ball down to the bottom of the ball is usually a waste of money and might have a negative impact on the tree.
For soils where the water doesn’t drain away well, spraying the sides of the holes with 3% hydrogen peroxide will help initial root establishment. This is especially good for tree holes dug in hard clay soils. It stimulates biological activity, loosens the wall of the hole and creates a more receptive surface for the tree roots to enter.
Running a perc test on tree holes is important if time allows
3. PLACING THE TREE
Container-grown trees often have root-bound balls. If so, soak the root ball in water and loosen the roots. Don’t worry about hurting the tree. Cutting and tearing the bound roots is the second best method. Ball and burlapped trees don’t need this treatment. Tightly bound roots have great difficulty breaking away and growing into the surrounding soil, and can prevent moisture from getting into the inside of the root ball.
I have planted many trees using bare root techniques and think you should consider it, although it’s not for everyone and doesn’t work well on trees that have extremely weak root systems.
See the Bare Root Information for more helpful advice on this technique. At the least, remove the excess soil that is almost always on the top of the ball and covering the flare. Uncover the true top of the root ball in other words. When planting bare-rooted plants, it is critical to keep the roots moist during the transportation and planting process.
It’s essential to remove any nylon or plastic covering or string, since these materials do not decompose and can girdle the trunk and roots as the plant grows. Studies have shown that even wire mesh should be removed to avoid root girdling because wire does not break down very fast, especially below 6” in the ground.
Correct Planting Height and Mulch Application
BACKFILL WITH EXISTING SOIL
Backfill with only the soil from the hole. No bark, sand, peat moss, compost, foreign soil or fertilizers go into the backfill. The roots need to start growing in the native soil from the beginning. If the backfill is softer than the surrounding soil, a “pot effect” is created in the ground which makes proper watering difficult and encourages roots to circle in the hole. Circling roots can eventually stunt, deform or even kill the tree. When the hole is dug in solid rock, topsoil from the same area should be used if possibe. Some native rock bits mixed into the backfill is beneficial. If you are planting in soils that have been highly disturbed or damaged, or compacted, add some mycorrhizal inoculum to the backfill material. Spraying the wall of the 3% hydrogen peroxide will also help.
Putting gravel in the bottom of the hole is a total waste of money.
SETTLE SOIL WITH WATER
Settle the backfill soil with water – don’t tamp. No feet, 2x4s or anything else. Simply let the weight of water settle the soil naturally. Water the backfill very carefully, making sure to get rid of all air pockets.
MULCH THE TOP OF BALL
Mulch the Top of the ball. After the backfill is settled and leveled with the surrounding grade, cover the disturbed area with a 1-inch layer of a 50/50 mix of compost and lava sand. Acceptable lava sand is red or black scoria that is the byproduct of lava gravel. Any volcanic rock material can be used if lava sand isn’t available and earthworm casting can substitute for the compost. Finally, add a 2-inch layer of shredded tree trimmings – but do not allow mulch to touch the trunk or trunk flare of the tree.
Do not ever plant grass over the tree ball until the tree is established.
Improper Planting Height and Mulching
4. TREE PLANTING NO-NOS
DON’T BUILD WATERING RING DIKES
If trees are planted correctly, these things aren’t necessary. Supposedly water rings form a dish that makes watering more efficient. Problem with that thought process is that when trees are backfilled with the existing native soil and mulch is properly applied on top of the disturbed area, moisture will stay in the root zone for a long time without the cost or inconvenience of the watering rings. If you build water rings around the trees, you have to tear them down at some point or you’ll have “watering bumps” around your trees forever. I am also not a big fan of the green water bags that are being commonly used these days. They shade the bark unnaturally and keep the trunk and flare wet. Plus, they look terrible.
STAKING TREES SHOULD BE AVOIDED
Hundreds of trees were planted on the original Radio Shack site Fort Worth. None were staked and none blew over.
Healthy trees that are planted properly rarely need to be staked. The ill-advised technique of staking all trees was probably started years ago by those who planted bare-rooted trees and mistakenly put soft potting soil in the hole as backfill. Staking is a waste of money and detrimental to the proper trunk development of the plant. In rare circumstances (sandy soil, tall evergreen trees, extreme wind, etc.) where the tree needs to be staked for a while, temporary staking should be done with flexible guying systems that allow the trunk to have some movement with the wind.
If staking has to be used for a short time, this is a pretty good system. It is loosely draped and allows the tree to move some with the wind.
Staking should only be done as a last resort – it is unsightly, expensive, adds to mowing and trimming costs, and restricts the tree’s ability to move and develop tensile strength and trunk diameter. It can also cause damage to the cambium layer, even if soft materials are used. Palms and other tall whippy trees are the exception to this rule. They usually do have to be staked for a while. Starting with smaller specimens usually avoids this issue. Never leave any kind of staking on more than one growing season.
Improper staking retards proper growth
DO NOT WRAP
Trunks of newly planted trees should not be wrapped – ever. It wastes of money, looks unattractive, harbors insects and leaves the bark weak when removed. Tree wrapping creates damage similar to when a bandage is left on your finger too long. If you are worried about the unlikely possibility of sunburn, it is much better to paint the trunk with a diluted latex paint that matches the color of the bark. If tree trunk protection is needed against sunscald on thin barked trees, such as ash, birch, linden or maple, white painting trunks is much better than trunk wrap. This ARS tested and approved method is effective at repelling insect pests as well as preventing sunburn.
There’s one situation where wrapping trunks might make sense. If the trunk of a tree has been physically damaged, painting the injured area with Tree Trunk Goop formula and then wrapping the damaged area with burlap soaked in Tree Trunk Goop will help the tree’s wounds heal much faster. The burlap helps hold the material in place as it protects and feeds the tree. Burlap isn’t necessary usually if my formula #4 is used. See Tree Trunk Goop in the Library https://dirtdoctor.com/organicguides/tree-trunk-goop/
Landscape contractors have admitted to me that brown paper wrap, tree stakes and guy wires and even the troublesome watering rings are added to newly planted trees for no other reason than to impress the homeowner.
Trunks should never be wrapping on newly planted trees. Proponents of wrapping say this will prevent borer insects. There must be some pretty stupid insects out there!
DO NOT PRUNE
It is bad advice to prune at planting to compensate for the loss of roots during transplanting or planting. Most trees fare much better if all the limbs and foliage are left intact. The more foliage, the more food can be produced to build the root system. Even low limbs and foliage should be left on the tree for at least two growing seasons to aid root development. The health of the root system is the key to the overall health of the tree. The only trees that seem to respond positively to thinning at the time of transplanting are field-collected live oak, yaupon holly and a few other evergreens. Plants purchased in containers definitely need no pruning, and deciduous trees never need to be thinned. Bare root trees need no pruning.
People don’t grow trees. Trees grow with people or sometimes in spite of people. For the most part, trees are tough, durable and easy to plant and transplant if treated in a sensible and natural way.