While out on design consults a common problem I run across is customers that have tree roots that are visibly pushing the sod above them up. It’s most common in neighborhoods that were built-in the last 10-20 years. The trees that were originally installed are now big enough that the protruding roots are both an eye sore and a pain to mow around. If they were close to a patio, walkway, or driveway they will likely be pushing the hard surface up causing cracking and buckling.
So why is this happening? Although there are trees that tend to root shallow, the main reason tends to be the clay below. If you’ve ever tried to dig through a yard that is sitting on heavy clay you surely understand just how difficult it can be. It’s the same for the trees.
Most trees send a majority of their roots out in the top 12-24″ of soil and then extend a smaller percentage down into the ground. This provides the trees with added strength and the ability to draw water and nutrients from multiple places. The problem with clay is that it is a lot like planting a tree in a few inches of soil laid over concrete. The clay is very dense and difficult to penetrate and offers very little in terms of nutrients. As a result, the trees will spread through the soft soil on top of the clay.
In most new construction sites the ground is not properly prepared before the landscape is installed. It can be a bit costly to bring the needed topsoil in and spread it across the site. Ideally a 12-18″ layer of topsoil would be installed which can cost many thousands of dollars. Instead of absorbing these costs, the site is left alone and sod is brought in and laid over top of the hard clay. In the long run the grass suffers due to lack of drainage, nutrition, and moisture retention. Similarly, the trees have nowhere to send their large roots except out along the top of the clay. If there isn’t enough topsoil over the clay, the roots will begin to stick out more and more.
There are other causes of roots sticking out but if you are experiencing this problem, I would take a second and dig around the area. If its heavy clay, it’ll be easy to tell. The shovel won’t want to go into it any more than the tree roots.
The solution to this problem can vary. If it’s purely cosmetic and is in the lawn, simply raising the grade and establishing a new lawn can be a permanent solution. If the roots are buckling driveways and walkways, the solution may require more complex measures. Simply cutting out the root may work in the short-term but new roots will cause future buckling and removing too many large roots from tree that is already struggling to get a grip could weaken it enough that it falls in heavy wind.
If roots are a problem at your house, make sure you get an expert out to evaluate what is causing the roots to stick up before taking action. When working with living, growing, moving things it’s best to make a long-term solution.
If you’re in South East Michigan, visit us at www.MillerLandscapeInc.com for more information about us and for our contact information.