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Are Magnolia Tree Root Systems Invasive to Home Foundations?

Tree roots are often erroneously blamed for foundation damage, according to The Morton Arboretum. Only the tiniest, threadlike roots may infiltrate foundation cracks. Shallow building foundations may sustain damage if the magnolia tree is massive.
  1. Function

    • Of the nearly 125 different magnolia trees, most develop shallow, wide-spreading roots in the top 1 to 3 feet of soil. Their roots also rarely branch and are much more snakelike and resemble floppy rope. Tree roots are opportunistic -- they grow blindly in all directions to reach fertile soil or a source of moisture.

    Considerations

    • Only in rare cases would magnolia tree roots potentially contribute to building foundation problems. Shallow footers may be moved or jarred by a large root, especially if the tree trunk is close by. The Morton Arboretum notes that in seasonal droughts, a magnolia tree's roots may pull away enough moisture to cause the soil under a foundation to subside.

    Size

    • Not all magnolia trees mature to the same size. Take tree dimensions into account -- larger trees create larger and more wide-spreading roots. A small star magnolia tree, which looks more like a shrub, would create less foundation concerns than a massive southern magnolia less than 20 feet away from the building.