We tried to cut down a dying oak tree in our yard not long ago, but the taproot went down several meters into the soil and made it more difficult than we thought it would be getting it out. I also thought the roots would be dead but they weren’t.
Tree roots, like the crown, keep growing a little bit for as long as a tree is still alive. Tree roots can keep growing for up to seven years after a tree has been cut down. The felled tree stump and roots also produce root sprouts and suckers to try and keep the tree growing.
Trees are amazing, and all this is fascinating – so let’s find out more about how tree roots grow and how you can stop them growing if you need to…
How Long Do Tree Roots Keep Growing?
In general, for as long as a tree is alive it keeps growing a small amount – and so do the roots.
However, tree roots can keep growing for up to seven years – after the tree has been cut down. The tree’s roots will keep growing as long as they continue to receive nutrients; however, the tree needs leaves in order to produce its food.
Now, from this, you’d assume that a chopped-down tree is dead and its roots can’t continue to grow without support from the leaves. Not so.
The survival instinct is strong in most plants, and the tree is no exception. A wounded tree will start to regrow leaves in order to keep feeding itself. Tree stumps and roots produce something called a “root sprout” or sometimes a “root sucker”.
These root sprouts are tiny clones of the original tree, and are a big part of its survival strategy. They can grow from the stump of a felled tree: you’ve probably noticed small, leafy branches growing from stumps.
They can also sprout from the roots themselves, so in the case of a large tree, will sometimes appear a good distance away from the original trunk, growing from the tips of the roots.
These sprouts can keep popping out of the roots and stump for up to seven years after the parent tree has been felled. Before you start to worry about a self-growing forest taking over your yard, it’s worth knowing that not all trees produce aggressive roots sprouts.
Pines, aspens, oaks, maples and palms: these trees will all die back when they have been felled, and their roots won’t try to regrow the tree. Willows, poplars, elms and some olive trees will try to survive by producing root sprouts.
How Do You Stop Tree Roots From Growing?
The answer to this is to remove everything when you chop down a tree. If you have a species that produces aggressive root sprouts, you’ll spend the next few years digging them up unless you remove all parts of the felled tree.
If you have one of these persistent trees, it’s a good idea to seek help from an expert arborist before chopping it down. They can arrange to have the whole stump and root system removed, which is costly, but can prevent future problems. You may also need to think about getting in dirt to fill the tree-sized hole in your yard…
Lower-tech measures include applying a special tree-kill chemical to the stump immediately after felling the tree. Using Potassium Nitrate on the stump won’t work, as it won’t reach the roots. One of the old ways to deal with the leftovers after felling is to paint the stump: sorry – all you’ll get here is a pretty-colored stump.
A great environmentally friendly solution is to get a goat. These greedy mammals will chow down on those tasty root sprouts for you. Adopting a goal is quite a radical approach, and it’s probably easier to get the human experts in…
Can a Tree Grow Back From Roots?
Yes, it can – or rather, some species will try to regrow after being chopped down. Willow, poplar, elm, and some olive trees are a few of the species that put out what are called “root sprouts” after they’ve been felled.
These sprouts are the tree’s attempts to regrow itself, and these little cloned branch-like growths will appear from the leftover stump and roots. After you’ve chopped down a tree, you’ll either need to remove all its underground structure as well as the main plant, or spend the next few years keeping on top of the root sprouts.
Will Cutting One Root of a Tree Kill it?
Cutting tree roots can be harmful for the plant. A tree has around six or seven main roots in its complex underground system, so severing just one will have an impact.
If you need to remove a root, sever it as far away from the trunk as you can. The closer the root is to the tree, the more stress you will cause the tree. Also, the wound left by cutting a root can let diseases enter the plant’s system.
If there are living tree roots causing a problem, the best thing to do is not touch it yourself, and call in an expert to take a look. They may be able to remove a root and apply a root barrier without harming the tree.
Is it OK To Leave Tree Roots in The Ground? (Do They Need To Be Removed?)
Whether you leave roots in the ground or not depends on the type of tree. Certain species, like the pine family, have roots that will rot down into the earth pretty rapidly after you’ve cut down the tree.
However, if you have one of the species we mentioned above that is determined to regrow itself, you will be battling root sprouts for the next few years.
Because tree roots can have a pretty widespread, these little sprouts can start popping up over a large area. It can be much easier to remove the root system when you fell a tree – provided you know how you’re going to backfill the hole afterwards…
What is The Best Tree Root Killer?
You can buy root killer easily at homeware stores like Lowe’s and Home Depot, and you can also order it from Amazon. The active ingredient is glyphosate herbicide, which is found in Roundup.
These are pretty harsh substances as you can imagine, and you’ll need to keep kids and pets well out of the way. There are homemade root killer recipes out there, involving ingredients including bleach, epsom salt, and our old favorite, vinegar.
We haven’t heard much positive feedback about homemade root killers unfortunately, so it might be time to try the chemical approach for once.
This short film shows you how to use a commercial tree root killer.
Can Tree Roots Break Through Concrete & Damage House Foundations?
Yes, tree roots can break through concrete and cause damage: but this problem is far rarer than you may have thought.
Tree roots, as we’ve already read, can be aggressive things, determined to promote the survival of their tree. However, they also don’t want to make things hard for themselves. Tree roots will instinctively head for the softer dirt where growth is easier. These roots don’t want to have to deal with barriers such as concrete house foundations.
(Important note. We’re not structural engineers here at Take a Yard, so we’ll always advise you to get an expert opinion if you have any concerns at all about your home.)
Where roots can start to cause a problem is with gaps and cracks in patios, paths, and sidewalks. The root will be happily growing away just under the surface when it encounters an obstacle: a concrete paver. If there’s a crack or a gap, it will grow towards it, seeking air and light. This can cause the concrete to crack and even rise up and buckle.
As well as looking unattractive, this can be a real tripping hazard. This is a problem if your tree is causing the sidewalk to bulge. This is one of those occasions where you might need to remove a root then treat it with a root barrier. Speak with an arborist if you notice any cracks or bulges start to form in the hardstanding around your tree.
We all love trees, and they’ll keep growing just a little bit both at the crown and roots if you let ’em.
However, if you must cut a tree down – try and get the whole thing or the stump and remaining roots will produce those suckers and sprouts if you’re not careful.
To be completely sure nothing will ever grow back, the best thing to do is use a commercial tree root killer as outlined in the video above – that way you won’t get any nasty surprises when you find the tree growing back again.
It’s happened to us before – regrowing trees can get quite big quite quickly while you’re busy doing other things. 🙂