Why Tree Roots Grow Above Ground (and What to Do About It)
Surface Roots 101
Many Calgary homeowners are surprised to see roots snaking across the lawn. It looks alarming—but in most cases it’s a predictable response to soil and water conditions. Roots need oxygen as much as moisture. In compacted clay soils or sites with shallow irrigation, oxygen is most available near the surface, so roots grow upward to where they can breathe. Certain species—poplars, elms, and spruce—naturally develop surface roots as they mature, especially where soils are tight or thin.
Risks and Annoyances
Surface roots lift pavers, trip pedestrians, and blunt mower blades. They can also suffer mechanical injuries from string trimmers, opening pathways for decay. In drought periods, exposed roots can desiccate; in wet springs, they can become slippery. Left unmanaged, these issues turn daily yard care into a nuisance and elevate liability on busy walkways.
What Not to Do
Never cut large surface roots to “solve” the problem. You may remove a significant portion of the tree’s anchorage or absorbing roots, leading to decline or instability—especially risky in chinook winds. Likewise, piling soil over roots to bury them suffocates the root plate and encourages girdling roots around the trunk. Both quick fixes cause long‑term damage.
Smart Solutions That Work in Calgary
The safest approach is to adjust the site around the tree. Expand the mulch ring to at least the dripline where possible; a 5–8 cm mulch layer protects roots from mowers, conserves moisture, and improves soil over time. Where turf is desired, topdress gradually—no more than 2–3 cm of soil per season—to avoid suffocating roots. Consider stepping‑stone paths or resin‑bonded gravel for durable, root‑friendly walkways. If a root is creating a severe trip hazard, consult an ISA Certified Arborist about careful shaving or bridging solutions that preserve function without compromising stability.
Prevention Through Planting and Watering
Choose species suited to your space and soil. Deep‑rooted species planted with adequate soil volume are less likely to surface. Water trees deeply and infrequently to encourage deeper rooting rather than daily, shallow turf cycles. During drought, a slow‑soak at the dripline supports roots where the tree needs them most and discourages shallow growth near the trunk. Finally, avoid compacting soils around trees with vehicle parking or frequent foot traffic—install defined paths to protect the root zone.
When Limited Root Pruning Is Appropriate
In rare cases—such as a single root lifting a sidewalk slab—an arborist may recommend carefully shaving or redirecting a portion of a root, coupled with load‑spreading repairs (rubberized pavers, root‑bridge details). This is surgical work with real risk; it demands professional judgement about species, stability, and drought exposure. The alternative is often re‑routing a path or accepting a gentle ramp over the root zone.
Hardscape Retrofits That Respect Roots
Flexible paving systems, permeable pavers, and cut‑outs enlarged to the dripline can solve trip hazards without harming trees. In Calgary’s freeze–thaw cycles, designs that allow slight movement outperform rigid slabs that crack repeatedly. Where budgets are tight, resin‑bonded gravel or stabilized fines provide firm, ADA‑friendly surfaces that weave between roots instead of fighting them.
FAQs for Calgary
FAQ 1: What should Calgary sites consider about this topic in winter?
Winter conditions in Calgary swing between deep freeze and chinook thaws. Plan work during dormancy when appropriate, protect roots with mulch, and schedule post-storm checks. For exposed locations, choose wind-firm species and ensure watering before freeze-up to prevent desiccation.
FAQ 2: How often should maintenance occur for why tree roots grow above ground (and what to do about it)?
Set an annual inspection with additional checks after significant wind or heavy, wet snow. Most sites benefit from a 2 to 5 year pruning cycle, adjusted by species, exposure, and risk targets. Document findings with photos to track trends and justify budgets.
FAQ 3: Which Calgary-specific species perform well here?
Hardy choices include linden, bur oak, hackberry, white spruce, and serviceberry. Avoid brittle or high-maintenance species near high-traffic areas. Match mature size to available soil volume and keep adequate clearances from utilities and sightlines.
FAQ 4: What are common mistakes to avoid?
Topping or indiscriminate cutting, burying root flares under soil or rock, overwatering in compacted clay, and ignoring bylaws such as the seasonal elm pruning restrictions. DIY work at height or near power lines is dangerous and should be left to certified, insured professionals.
FAQ 5: What should Calgary sites consider about this topic in winter?
Winter conditions in Calgary swing between deep freeze and chinook thaws. Plan work during dormancy when appropriate, protect roots with mulch, and schedule post-storm checks. For exposed locations, choose wind-firm species and ensure watering before freeze-up to prevent desiccation.
FAQ 6: How often should maintenance occur for why tree roots grow above ground (and what to do about it)?
Set an annual inspection with additional checks after significant wind or heavy, wet snow. Most sites benefit from a 2 to 5 year pruning cycle, adjusted by species, exposure, and risk targets. Document findings with photos to track trends and justify budgets.
