Effects of Flooding on Trees and What to Do About it!

Flooding Kills Trees!


flooded tree2.jpg

We’ve had some crazy flooding today! I mean, it has been INTENSE! Over 3 inches in just 24 hours here, and flood warnings have been issues all the way from Texas to Canada!

but here’s the scary thing; there are some big changes that happen in flooded conditions and many of them GREATLY affect your trees!

Here’s what you need to know about how a flooding relates to your trees, the dangerous conditions it can cause, and what you should be doing now to go ahead and decrease the likelihood of catastrophe later!

1.       What Happens That’s so Bad? – in a flooded soil, nitrogen levels in the soil get completely sapped within 1-2 hours. You may be thinking that it’s because the nitrogen gets “washed” or “leached” out of the soil, but it actually happens a bit differently than you might think:

Roots from trees and plants “breath” oxygen, but sometimes when soils become flooded, little room is left in the soil for oxygen to accumulate and become available to the roots.

When this happens the tree has a wicked cool survival mechanism; it stops breathing oxygen and start “breathing” Nitrogen! Man it would be cool to just be able to switch what we breath just like that right?

Nitrogen is Key for a Healthy Tree!

Nitrogen is Key for a Healthy Tree!

Sidenote: TREES NEED NITROGEN TO FUNCTION! That’s why all of your neighbors put down fertilizer for plants that is typically rich in nitrogen!

Okay, so trees and plants breathes nitrogen in an emergency, BUT it is an inefficient way for the tree to breath, and it goes through it almost ALL of the nitrogen in the soil within a matter of hours (1-2 typically!)

2.       What Does This Do? – Initially, nothing! In fact, it’s great because it winds up keeping the tree alive when it should be suffocating! But there’s a long term affect as well...

Because the tree needs Nitrogen to function, and it has now “breathed” it all away, it has no nitrogen needed to function!

here’s a few things that can happen to a tree that doesn’t get the nitrogen it needs to function:

Flooding Causes Sick Trees!

Flooding Causes Sick Trees!

-          Stunted growth, or no growth
-          Ugly discoloration of leaves
-          No chlorophyll production – (this  produce it’s food)
-          Protein loss
-          Lack of fruit and flower production
-          Root death
-          Tree death

Not great symptoms right? Flooding can be one of the worst things that can happen to your tree because it literally takes away one of the main building block of all trees and plants – NITROGEN.

3.       What Can I Do About it?

the good news is that it’s very easy to reverse the effects of flooding!

Basically all you have to do is fertilize, but before you go just dumping a bunch of chemicals that you know nothing about, here’s 2 of the best ways to fertilize; the first, is done by a professional, because it requires expensive equipment. The Second, anyone can do with the right tools!

Deep Root Fertilization –

This is probably my favorite method, because it’s simple and affective!

A slow release fertilizer is added to a “spray rig” that mixes the nitrogen, along with any other chemical, medicine, or nutrient that is needed by the tree or shrub (Read on, we’ll learn how to find this out later!)

Deep Root Fertilization

Deep Root Fertilization

The mixture is then pumped at high pressure into the soil around 6”-8” below the surface through a device called a “feeder probe,” which sprays the mixture in all directions to get to all of the tree’s roots.

Why I like it  - I really like this because, when a granular spread is applied, typically the plants that are around the tree will steal the nutrients before the tree roots can get them! Deep Root Fertilization bypasses other root systems and gets STRAIGHT TO THE ROOT OF THE PROBLEM 😊

It’s also great because it expands the soil, allowing more room for new oxygen to fill the soil (especially great after a flooded soil!

Vertical Mulching –

If Paying a Professional is simply not an option right now, then here’s another method you can do to restore your trees after a flood!

Vertical Mulching

Vertical Mulching

What you’ll need –
1.       high powered battery drill, or lower powered, corded drill
2.       a 1”-3” “earth auger” bit that fits your drill ...  you can find a great one HERE
3.       fertilizer – slow release, organic kind if possible. I like Milorganite personally :D
4.       compost!

 How to do it:
1.        Drill holes in the soil that are 1”-3” wide, and 6”-8” deep. Stagger the holes in a brick-laying pattern all throughout the soil underneath where the tree’s canopy is. We consider this area to be within the “drip-line,” or area underneath the treed
2.       Backfill 2” of each hole with an organic, slow release fertilizer.
3.       Backfill the remainder of the hole with organic compost.

Fertilize at least to the drip line!

Fertilize at least to the drip line!


Why I Like It - This is great because it’s almost as effective as Deep Root Fertilization, yet it can be done easily by you at home with the right tools and a little elbow grease! Much like Deep Root Fertilization, this too can be a great way to allow the soil to fill back up with air that your trees and plants can use!



There’s one more vitally important thing to consider when thinking about fertilizing your trees. This is probably the most important thing because if you get it wrong, you could wind up harming the tree even more than if you did nothing at all:

Doctors diagnose issues before prescribing treatments ... you should too

Doctors diagnose issues before prescribing treatments ... you should too

do you know how the doctor prescribes you medicine? He/She does it by first going in and checking pulling a test right? maybe they’re checking for the flu, maybe Lyme disease, but ultimately, A GOOD DOCTOR, is going to use science to determine what is going on.

The same method must be used to determine how much fertilization needs to be done. You must take a scientific approach and find out how much nitrogen and other nutrients are already in the ground, so you can know how much to apply; and the way we do this is by doing what I call the….

soil samples give a clear picture of what you need to fertilize with!

soil samples give a clear picture of what you need to fertilize with!

Targeted Nitrogen Technique (or TNT) – pretty fun right? To apply the Targeted Nitrogen Technique, what you will need is a soil sample, first, diagnosing how much fertilizer is already in the ground!

Every State has an agricultural “hub” of sorts which is designed to educate the public on plant care, assist the public in plant care, and push research to further our understanding of plants based in each state. It’s called the Agricultural Extension, and what you’ll need to do is send a soil sample to them for analysis.

To find your state’s agricultural extension, and where to get advice on sending in soil samples, type this into Google: ”(Your state) agricultural extension soil sample”

follow their instructions for taking and sending in a soil sample (along with their fees!), and they will send you back a comprehensive report showing you exactly what your trees and shrubs need to get back on track!

Among other things, it will tell you how much nitrogen to “target” when fertilizing your trees! Measure and apply your fertilizer according the soil sample report, and your trees will thrive like you wouldn’t believe!

I’m looking out the window while typing this as the rain and wind continue to pound the earth, I realize how many trees are going to be set up for failure from this. Remember to fertilize your trees, and your tree will not be one of them!


flooded tree.jpg

As always, don't hesitate to reach out to me with your tree questions at the info below or leave me a comment :D

My Best, Always, 

Matt Latham
ISA Arborist #TX-3737A