CO-Horts Blog

Thursday, May 17, 2018

Tree Planting No-No's!

Posted by:  Amy Lentz, Weld County Extension

It’s planting season all across Colorado, from agricultural crops to flowers to trees. It’s the latter that I want to address today in this blog…planting trees! Our towns and cities are growing (fast!) and with this comes the planting of a LOT of new trees, both in public spaces and on private property. Planting trees in the correct manner is the most beneficial thing you can do for a tree’s health as it will be the foundation of the tree for the rest of its life. If these newly planted trees start off at a disadvantage, it could invite many insect, disease and other tree health issues down the road. And let’s be real, trees are not cheap! They are quite an investment that will eventually pay off down the road once the tree matures…if it’s been properly planted and cared for as it gets established.

Being a tree in Colorado isn’t all that easy with our dry climate, wide swings in temperature and less than ideal soils in most locations (among other hurdles). This makes it ultra-important to help these newly planted trees get off to a good start in life. If planted incorrectly, these trees can be doomed with a death sentence from the day they go in the ground, but you won’t see it right away. In many cases, a poorly planted tree will not show symptoms of poor planting until a few years later.

Here’s my list of 5 Tree Planting No-No’s:


You should plant the tree so the root flare (where the tree’s trunk meets the top of the roots or the top of the root ball) sits just slightly above the existing soil level, 1 to 2 inches. Measure the root ball before you start digging and check the depth periodically as you go down. You can always remove more soil if the hole is too shallow, but soil that has been added back into the planting hole will not act the same as if it were not disturbed. Instead, it will settle and the tree will likely sink causing it to be planted too deep.


The hole should be 3 times the width of the root ball of the tree and have sloping sides. This is especially true for trees grown in containers, as their roots need to adjust from growing in a barky potting mix to growing in heavy soils. Digging the hole wider will loosen the soil so the roots can grow and adjust more easily to the native soil.


This tree was easily pulled from the ground years after it was planted. It had a very poor root system due to the wire basket being left in place at planting. A Big No-No!

I can’t stress this enough. I have seen trees succumb to a slow and horrifying death because wire baskets have been left in place. Not only is the tree you've invested in dead after a few years, you have also lost years of growth and will have to start over. Burlap and rope should also be removed as these will not break down fast enough in our Colorado soils, hindering the root growth of the tree and causing the same demise. So take the time to remove the basket and place the tree gently into the planting hole. This is also a good time to check for circling roots or roots growing across the base of the trunk and direct them away from the base of the tree.


Just say no!

I have seen a lot of this lately! Trees take up water and nutrients from their roots, not their trunks. Therefore, the trunk does not need mulch to help conserve water or protect the tree. Instead, it hurts the tree. Having mulch piled up around the base of a tree can lead to the wood rotting and inviting pests and disease to attack the base of the tree. Don't get me wrong...mulch is a great thing! I love seeing trees with good-sized mulch rings underneath as this creates a favorable environment for the tree’s roots and keeps mowers and string trimmers away from the tree. So use mulch, just use it in a 2-3 inch layer out to the drip line for a new tree, keeping it a few inches away from the base of the trunk.


Too tight.
Just right.

A newly planted tree needs encouragement to grow strong roots. Think of it like an arm in a cast…without the ability or need to move the muscles, they become weak. If we baby a newly planted tree too much by tightening the staking straps to the point of no movement, the tree will not form as strong of a root system because it doesn’t have to in order to remain upright. Staking straps should have a little wiggle room so the tree can still sway in the wind. Furthermore, if they are too tight, they could girdle the tree’s trunk as it grows in size. Straps should only be left on for the first year a tree is in the ground.

There are many other helpful recommendations when it comes to planting trees. For the complete story, check out the following resources from CSU:

Tree Planting Steps - Colorado Master Gardener Garden Note #636

The Science of Planting Trees - Colorado Master Gardener Garden Note #633

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