Magnolia Root System – Are Magnolia Roots Invasive

Tree Along House
magnolia roots
(Image credit: fasterhorses)

Nobody can deny that magnolia trees in bloom are a glorious sight. Magnolias are so commonly planted in warm regions that they have become almost emblematic of the American South. The fragrance is as sweet and unforgettable as the huge, white blossoms are lovely. 

Although magnolia trees are surprisingly low maintenance, magnolia tree roots can cause problems for a homeowner. Read on to find out the type of magnolia tree root damage to expect if you plant these tree close to the house.

Magnolia Root System

Magnolias, like the glorious southern magnolia (Magnolia grandiflora), the state tree of Mississippi, can grow to 80 feet tall. These trees can have a 40-foot (12 m.) spread and a trunk diameter of 36 inches (.9 m.). You might think that magnolia tree roots head straight down in order to stabilize these big trees, but that is far from the truth.

The magnolia root system is quite different, and the trees grow large, flexible, rope-like roots. These magnolia tree roots grow horizontally, not vertically, and stay relatively close to the soil surface. Because of this, planting magnolias near houses can lead to magnolia tree root damage.

Planting Magnolias Near House

Are magnolia roots invasive? The answer is yes and no. While the roots are not necessarily invasive, you may get magnolia tree root damage when the trees grow too close to your house. Most tree roots seek a water source, and magnolia tree roots are no exception. 

Given the flexible roots and the shallow magnolia root system, it is not difficult for magnolia tree roots to head for cracks in your plumbing pipes if the tree is planted sufficiently close to the house. Most tree roots do not actually break water pipes very often. However, once the pipes fail at the joints due to aging of the plumbing system, the roots invade and block up the pipes. 

Remember that the magnolia root system is very wide, up to four times the width of the tree canopy. In fact, magnolia tree roots spread farther than those of most trees. If your house is within root range, the roots can work their way into pipes under your house. As they do, they damage your home’s structure and/or plumbing system.

Teo Spengler

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.