Q: Tree roots have come up to the surface in our lawn. ItБs so bad the lawnmower blade hits them. What is causing this, and what is the best way to deal with them without harming the tree? A: There are several reasons tree roots come up to the surface. Although some kinds of trees, such as poplars and ornamental cherries, are prone to produce surface roots, usually theyБre a sign of poor soil conditions. Heavy clay or compacted soils lack the air and moisture necessary for proper root growth below ground, so roots are forced to come up to the surface to find what they need for survival. Unfortunately, as the tree grows, surface roots also increase in size, and if they are on a lawn they can become so large they can make mowing difficult, if not impossible. Covering surface roots with soil wonБt solve the problem. Adding too much soil at one time can suffocate tree roots, while adding a bit at a time is pointless because the soil simply dissipates and disappears into the lawn. If necessary, surface roots can be removed, but it must be done properly or it could harm the tree. During the dormant season, remove only one large root or two smaller ones per year. Allow at least 10 inches of distance from the trunk for every inch of the diameter at ground level before making the cut. To prevent the likelihood of disease problems, first dig a trench around and under the root; then use a clean, sharp lopper, or in the case of very large roots, a pruning saw to make a clean cut. Finally, do not apply pruning paint. If all goes well, new roots will form and grow from the cut end.
Of course, the best longterm solution is to remove the lawn where the surface roots are causing a problem and turn the area into a garden bed. YouБll have a wonderful new garden space to enjoy and you wonБt be forced to spend hours of backbreaking work every dormant season removing roots and/or replacing broken mower blades. Q: Twenty years ago, I built a treehouse for my children. It is still there, suspended by 1-inch rope between four fir trees that are clustered together. I am going to take it down but the rope has become buried deep in the bark of the growing trees. Do I pull it out or leave it and just let the tree envelop it? A: This situation illustrates why we shouldnБt wrap anything tightly around the trunk or branches of a tree. As the tree grows and increases in girth, if wire or rope is left in place encircling a branch, over time it will cut into the tree, causing a condition known as girdling. Girdling can harm a tree in two ways. First, it blocks nutrients from moving past the constriction, preventing carbohydrates from reaching the roots. If the girdling occurs on a main trunk, it can lead to stunted root growth and endanger the stability of the tree. If girdling is severe, you will notice a large bulge made up of blocked nutrients above the restriction. The second problem is that if the tree grows around and envelops the encircling material, it can create a weak spot where the tree could break in a windstorm or a heavy snow. If the rope can be removed without seriously harming the bark, the damage is minimal and you probably donБt have to worry about it.
If the rope is enveloped and canБt be easily removed from a trunk or major limb, and the tree is located where falling branches could cause harm, call in a certified arborist to assess your tree.
Tree and yard owners are often faced with the problem of a tree s exposed surface roots. Tree roots that grow on the surface are difficult to mow or walk over and can affect the growth and health of nearby grass and ground covers. The usual response to remedy the situation is either to cut the roots or add fill soil over the roots and then replanting grass or ground cover. However, cutting out surface tree rootsPis not advisable as tree roots offer structural support and provide a nutrient flow that supports growth and vigor. When damaged, tree roots attract pests and pathogens. Trees that experience root removal or serious root damage can express top canopy death on the side the roots were harmed. Removing roots can also introduce rot into the root, the base, and the trunk of your tree. Adding supplemental soil to cover roots can also harm your tree. You can, however, add anPadditional cover like mulch over roots to smooth out the surface of the landscape. Adding extra dirt,Pon the other hand, can reduce the concentration of soil oxygen needed for roots to survive, and trees may begin to show symptoms immediately or decline over time upon covering them. Ultimately, the best advice for gardening or landscaping in a yard that has surface tree roots is to leave them alone and incorporate them into your designs. Don t grow your garden or introduce small ornamentals near a tree s surface root system (its life-support system, essentially) as introduced extra vegetative competition may or may not survive against these large trees.
Having plants that heavily compete for nutrients and light is never good within the tree s the tree may not suffer but the cover plant will lose vigor,Pprobably struggle to thrive, and will cost you the price of the plant plus the planting time. P A better way to deal with surface roots is to cut a bed around the offending root system and cover with coarse mulch, making sure to not add more than an inch of extra soil. Trying to establish even a patch of tolerant grass or ground cover among the surface roots can often be difficult, andPit might actually be impossible to do because of natural tree root toxins produced by certain tree species. In addition to the root injury itself, other visible symptoms of injury may include small, off-color leaves, premature fall color, suckering along the main trunk, dead twigs throughout the canopy of the tree, or even death of large branches. The types of tree injury will vary byP, tree age, the health of the tree, root depth, type of fill and drainage. Trees that are usually severely injured by additional fill includeP,P, P, and many oaks,Ppines,Pand spruces. P Birch and hemlock seem less affected by rootPfillPdamage than other species, but elms, willow, London plane tree,Ppin oak,Pand locust seem to be the least affected. Older trees and those in a weakened state are more likely to be injured than younger, more vigorous trees when it comes to soil fill damage.