Yards with large growing trees often plagued with surface roots, which hamper lawn maintenance chores and can crack sidewalks. More than anything, they are just not appealing to the eye and potentially dangerous under foot.
What to do . . . here are some suggestions on dealing with surface roots and some insight into what causes them.
Many popular landscaping trees simply have shallow roots. These trees include Norway Maples, Red Maples, Silver Maples, Willows, Aspens, Pin Oaks, and Beeches. Actually any large tree can develop surface roots eventually, it is how they grow! But there are other aspects that contribute to this problem.
Poor soil quality can produce surface roots
Tree roots of most trees are found in the top 12 inches of soil. These roots rarely grow very deep unless the tree is planted in loose and sandy soil. Compacted or clay-based soils cause surface rooting, especially in urban areas where these types of soils are found. Rain and wind erode the soil around the roots and expose them.
Oxygen deficiency can cause surface roots
Roots need oxygen to keep the tree alive. In compacted soil, the roots grow up to the surface to get enough oxygen to survive. Often, trees with surface roots are struggling to breathe and to adapt to an environment that is not ideal for the health of the tree.
What to do with surface roots?
Coping with a tree or trees with surface roots is possible with these important suggestions:
Most important . . . do NOT cut surface roots!
No matter how enticing, do not cut the offending roots. Any cuts invite diseases and harmful insects. Further, these cuts can also negatively impact a tree’s stability, making it more likely to fall over in a bad storm. Cutting roots kills thousands of tiny “feeder roots” that allow the tree to absorb water and nutrients, leading to dieback in the canopy or death of the tree.
Apply a material mix at the base of the tree to manage surface roots
By mixing equal parts of topsoil and compost and then applying two inches of the mixture around the base of the tree helps deal with surface roots. Sow the area in late summer with shade-tolerant grass seed, keeping it well-watered. If the roots are still prominent within a year, add another two inches of the mixture and reseed. Remember, there is a risk of suffocating the tree if you add more than four inches of soil to the area beneath an existing tree, so do not do it!
Planting drought-tolerant groundcover under the tree is another suggestion, thus avoiding the need to mow.
Use mulch to cover surface roots. The best choice is to put down four inches of mulch made of wood chips underneath the tree. This helps level the area while keeping roots cool and moist and allowing them to breathe. Again, do not put down more than four inches, and do not pile mulch against the trunk.
Avoid planting trees with shallow root systems
If soil is compact or clay soil, the tree will inevitably have some surface roots. Some trees are way more likely to develop surface roots than others. Avoid well-known surface rooters like aspens, beeches, river birches, certain maples (red, silver, sugar, Freeman, and Norway), pin oaks, spruces, and willows. These trees have inherently more shallow roots and are more likely to pose a problem in your landscape.
Choose trees with deeper root systems
Some trees have deeper root systems. These trees will make much better options in your landscape and are way less likely to develop surface roots. Black gum, blue atlas cedar, ginkgo, golden rain tree, horse chestnut, certain oak varieties (red, swamp white, white, and willow), planetree, yellowwood, and zelkova are some of the best options.
Smaller trees have less troublesome roots
Trees that mature at under 30 feet tall will usually not have roots large enough to cause major problems. If size is not as important to you, consider varieties like cherry trees, dogwoods, magnolias, mimosas, Japanese maples, paperbark maples, redbuds, and lilac trees, just to name a few.
Avoid planting your tree too deep
Surface roots will not be stopped by deeply planting your tree. It is recommended to plant trees two inches above grade (but ensuring the root ball is not exposed, or it could dry out and be more vulnerable to winter damage).
Trees need room to grow
If you have a paved surface nearby, give your tree space. Large-growing tree should be planted at least six feet away from these surfaces. If you want to plant your tree between a sidewalk and a street, make sure the planting spot is at least eight feet wide with no utility lines overhead. Otherwise, choose a smaller variety. As some cities have restrictions and specific guidelines on planting, check with your local forestry department before planting.
There are a wide variety of methods available to manage surface tree roots. The professionals at Arborist Now can help you choose the best approach for your trees, and care for their overall health!