Example Article for Broadwater County Extension Agent
How to Kill a Tree
Author: Allison Kosto, MSU Broadwater County Extension Agent
Article Published: 09/04/2026 Volume: 5 Edition: 09How to Kill a Tree
Allison Kosto
MSU Broadwater County Extension Agent
If you’ve lived in Montana long enough, you know that it is really quite easy to kill a tree here with little to no effort. It can be a little frustrating because trees are expensive and it takes quite a bit of time and effort to plant it and keep it alive. We have a naturally arid environment (meaning little rainfall) with alkaline soil (high pH) which makes keeping trees alive a challenge. While there are a lot of different things that can truly kill a tree, here are a few of the more common and easily preventable mistakes.
Planting Depth:
Specifically, planting too deep is a widespread problem. Trees should be planted so that the root flare, which is the point in which the trunk widens into the roots, sits at or above the soil surface. When a tree is planted too deep then the trunk tissue is in constant contact with the soil. This is a problem because trunk tissue is not designed for this. The tree will likely never thrive, have increased stress and eventually it can lead to trunk rot and fungal infections.
Similarly, don’t pile mulch against the trunk. Mulch is encouraged and provides lots of positive benefits to the tree, including moisture retention and reducing plant competition. However, if it is tight up against the trunk it can also cause issues just like being underground. Leave 2 to 3 inches of space between the trunk and mulch.
Girdling Roots:
In addition to planting too deep, there are a few other common planting errors. Girdling roots is a situation that happens when a tree has been left in the pot too long. The roots will encircle the pot, and care needs to be taken to straighten, loosen and sometimes even trim prior to planting. If you leave them as is, eventually the tree will strangle itself.
Improper Pruning:
One of the worst pruning errors you can make is “topping trees.” This is a situation where the top of the trees is pruned to all the same level, effectively removing the main leader of the tree. This is stressful for the tree, which will respond by sending out water sprouts all over the tree. These are vertical shoots that are weaker than traditional new wood and lack the structure needed for long-term survival. Topping trees also leaves large wounds that will not heal correctly and open the door to bacteria, fungi and insects. Other pruning errors include removing too much canopy, incorrect cuts and not sanitizing pruning shears.
Watering (or lack thereof):
Probably the easiest way to kill a tree in our county is simply not to water it. All trees need supplemental water in our environment, especially as they establish. There are a few trees such as Rocky Mountain Juniper that you can reduce watering as they mature but in general all trees will continue to need supplemental water throughout their lifespan to truly thrive. This means more than lawn irrigation which typically only soaks the top 6 inches of soil. Trees should be soaked once a week during the growing season making sure the water gets at least 12 inches deep. You should even water in the winter as long as the ground isn’t frozen or snow-covered. This is especially important for evergreen trees which will continue to transpire moisture through their needles even in the winter.
Really, the list could go on and on. However, if you can follow the guidelines above you will hopefully get started on the right foot to help your trees arrive and thrive in adulthood.
For more information about tree, tree care or identifying tree issues, contact MSU Extension in Broadwater County at 406-266-9242 or allison.kosto@montana.edu.
