Have you ever seen a mature tree that has fallen over? Ever notice that the roots are like a pancake beneath the tree? Very few trees hardy on the Canadian Prairies have deep tap roots: Pines, Oaks, Willows, Silver Maple, Walnuts, Amur Maple, Elms and Ash. In warmer climates Sweet Gum, Eastern Redbud, White Mulberry, Black Gum, Fig Tree and more.

Most tree roots (and shrubs) are in the top three to six feet of the soil, spreading widely to six to twenty feet beyond the branch spread. The spread is to allow the tree to take the most advantage of rainfall, without being hindered by its’ own canopy. It’s one of the reasons that it is hard to establish shrubs and perennials around mature trees. There is much competition for water from the tree roots.

Why do tree roots surface? Compaction of soil around the plant, for one. The young tree was probably planted in fluffy, newly amended soil. Over the years people, animals, lawn mowers and even rain have slowly tamped the soil down. Another reason tree roots are exposed is run-off, water from rain or snow melt simply moves the soil to a lower elevation.

The number one reason roots come to the surface is that the roots are seeking oxygen. Roots need oxygen to function. Good soil is a combination of air pores, organic matter, rock particles (minerals), little tiny creatures and retained water. Compaction and heavy clay soils eliminate air pockets, hence roots migrate upwards. Waterlogged soil has few air pockets, the tree in the picture is close to a river that has been known to flood. The water table can be very high here. Tree roots are powerful in their search; have you ever seen the roots of a tree buckle pavement? (Street trees being some of the most stressed trees on the planet. Harsh place to grow!)

So, what to do if your roots are showing? On a mature tree no need really to do anything, the tree has adapted. If it’s doing fine, don’t worry. Try not to damage the exposed roots as wounds can allow in pathogens. If you don’t like the look you can cover them with soil but only to the level where the roots flare out from the trunk. Never, ever, ever, never bury the trunk of tree! If you’re watering, remember the the most viable roots are out beyond the branches and water there.

Cheers! Hope you can find some shade in this summer heat!