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How Big Is The Root System Of A Magnolia Tree?

Tree roots have always been a special concern for homeowners. And it’s not surprising because root systems can cause a lot of trouble, especially if we’re talking about a small yard.

The root system of a magnolia tree is as big as its crown. This is a general rule, so the bigger the tree, the bigger the roots. The roots extend about the same width as the branches.

But this is not always true. Some large magnolia species can have a root system several times larger than the above-ground part. For a tree to have such roots, it needs to grow for many years under ideal conditions in the wild. In an urban environment, this is hardly possible.

On the other hand, young trees usually have smaller roots than the top part of the tree. This is because the tree first creates branches and leaves and only secondarily makes their equivalent in roots.

It also depends very much on the growing conditions. In hard and rocky soil, the root system will be noticeably smaller than in loose soil. Also if the soil is sufficiently moist and nutritious the tree does not need to create a large root system because everything it needs is already there.

Read more: Tips On The Care Of Magnolia Tree

The reason why old trees have a wider root system than the crown is the fact that in maturity, trees slow down their growth rate. At the same time, the soil beneath the tree is depleted and it is constantly looking for nutrients, spreading its roots further and further.

how big is the root system of a magnolia tree

Do magnolia trees have deep roots?

Magnolia does not have deep roots, its root system is superficial. However, it all depends on the size of the particular tree. If the tree is more than 30 feet tall, its roots are at least 10 feet deep.

Also, different species of magnolia can have different depths. Very large specimens may have roots as deep as their width. This is due to the fact that the tree needs to cling heavily to the ground to withstand strong winds.

Also, if you are constantly watering and fertilizing the tree, the roots may not be too deep. This is especially true if the magnolia grows in a small area with little sunlight.

Do magnolia trees have damaging roots?

Magnolia has no destructive roots. In general, its roots are pretty thin and spread out in the upper layer of soil. Only some part of the root system is thick and strong, but in general, these roots are directed vertically into the depths to support the tree.

However, under certain circumstances, the roots can have a destructive effect. For this to happen the tree must be large (at least 15-20 feet tall).

Most often, a sidewalk can be damaged by magnolia roots. If the tree grows too close to the sidewalk, the roots may damage it a little. However, nothing critical will happen, just a few cracks.

So plant magnolia trees at least 5 feet away from walkways, sidewalks, or driveways.

Will magnolia tree roots damage house foundations?

Magnolia roots can damage the foundation of a house. This is possible if the tree is large. To have a root system capable of destroying the foundation, the magnolia must be about 20 feet tall.

For this reason, plant the magnolia at least 30 feet away from the house. The same goes for other buildings, such as a garage or barn.

Planting too close can not only result in foundation damage but also increased humidity in the house.

If your magnolia is growing too close to the house, you need to replant it. Read how to do this properly in How to transplant a magnolia tree?

Another solution to this problem is to prune your magnolia tree regularly. Every year, shorten its young branches, leaving only a few buds on each branch. Also, water and fertilize the magnolia regularly.

If the magnolia is up to 10 feet tall and wide, it is unlikely to have the strength to damage the foundation.

are magnolia tree roots invasive

Are magnolia tree roots invasive?

Magnolia roots are invasive. This means that under certain conditions they can damage both the objects around them and prevent the growth of other plants.

Of course, compared to Silver Maple roots, magnolia roots are not as aggressive. However, you need to follow some rules for growing magnolias.

First, stick to the recommendation for planting distance to the house and other objects. You can find them above.

The second is the difficulty of growing shade-loving plants under a magnolia canopy. The surface roots of magnolia plants are quite fine and branchy as a result they suck out a lot of water. They can also interfere with the growth of other plants.

To be successful at this, plant larger varieties of plants under the magnolia. Larger plants can compete with the magnolia for water and minerals. The distance between the trunk and the plants should be at least 1 foot.

Water the ground under the magnolia canopy regularly to avoid the dry shade effect. Also, fertilize all of these plants with a multi-purpose fertilizer.

One last thing to do is to prune the roots of the magnolia once a year.

Can I cut magnolia tree roots?

You can trim the roots of the magnolia if you need to. Moreover, in some cases, it is even necessary.

As a general rule, do not cut the roots of the magnolia closer than 2 feet from the trunk. Otherwise, you might touch too many roots and the leaves will turn brown.

The first time you may need to trim the roots is to keep them from spreading further than a certain area. Take a trench shovel and stick it on the edge of the area you don’t want the roots to spread beyond.

Step by step, go all the way around the border and trim the magnolia roots. Use a saw or an ax to remove the larger roots.

The second case is pruning the roots under the tree canopy. This is to make room for the roots of shade-loving plants that grow under the magnolia. To do this, use a spade.

Dig all the soil under the tree canopy, but do not damage the roots of the plants that grow under the magnolia tree. Also, do not dig closer than 2 feet to the trunk.

Magnolia tree roots above ground

magnolia tree roots above ground

Sometimes there is a situation where the roots of the magnolia can appear on the surface of the ground. This can happen because of heavy rains or because the roots increase in size and rise slightly above the ground.

This is a common thing that happens to many trees. But in this case, the roots can easily be damaged mechanically. So you need to cover them.

First of all put a thin layer of soil on top just to cover the roots from the sun. The layer of soil can be about 1-2 inches.

Next, spread a layer of mulch 2-3 inches thick. This will prevent the soil from eroding and reappearing roots.

Use organic matter as mulch. The harder the mulch the better, so pine bark is best.

Spread the mulch around the magnolia tree as wide as the branches will extend. However, do not put it on the trunk of the tree. There should be a gap of at least 1 inch between the mulch material and the trunk.


Thursday 11th of April 2024

We have a magnolia we planted about 3 year’s ago. I’m afraid it’s to close to our septic lines does it have a taproot?

Igor Viznyy

Friday 12th of April 2024

Hi Brenda. It's good to think about the placement of your magnolia in relation to the septic lines! Magnolias generally do not have a traditional taproot. Instead, they tend to develop a wide-spreading system of shallow roots. These roots extend horizontally from the tree in all directions, often going quite far but usually staying within the top 10 to 20 inches of soil.

Given their spreading nature, magnolia roots could potentially interfere with nearby septic lines, especially if the tree is planted very close to them. The roots might grow towards the septic lines in search of moisture and nutrients, which could cause problems down the line.

If you're concerned about the proximity of your magnolia to the septic system, it might be wise to consider relocating the tree while it is still relatively young and manageable to move. This could prevent any future issues with your septic system.


Saturday 10th of June 2023

My next-door neighbor has a magnolia tree growing about four or 5 feet from the retaining wall between our properties. Their property is about 6 feet taller on their side of the retaining wall. The wall is starting to crack on my side from the magnolia tree roots. What can be done?

Igor Viznyy

Sunday 11th of June 2023

Hi Alan, You definitely need to discuss this issue with your neighbor. This can be solved by using a tree root barrier on the neighbor's side.