The Real Culprit

 

The Real Culprit: Improper Tree Planting and Watering — Not Just Girdling Roots

By Paul Weaver, ISA Certified Arborist – Kansas City

We need to have a real conversation about tree decline — especially in urban environments — and it starts with this: girdling roots may be a symptom, but they are rarely the primary problem. I know it’s convenient to point the finger at a visible girdling root and declare case closed. But let’s be honest — most of the trees we see in Kansas City neighborhoods, business parks, and streetscapes didn’t stand a chance from the moment the shovel hit the dirt.

Why? Because they were planted improperly, irrigated sporadically or excessively, and maintained like they were annuals. Yet here we are, decades later, still publishing papers that focus on girdling roots as though they independently sneak in at night and choke the life out of trees. It’s time to shift the narrative.

The Study That Sparked the Debate

The 1984 study from the University of Massachusetts' Shade Tree Laboratories, led by Francis W. Holmes, is often cited when girdling roots are discussed. It’s a long-term, well-designed investigation involving artificial girdling devices on various maples. This study demonstrated that complete circumferential girdling — even artificial — can lead to eventual decline and mortality. But here’s the problem: it creates a false sense of certainty.

The research sidesteps a discussion of initial planting depth, root flare, and soil compaction — the very real and preventable conditions that produce the need for such an experiment in the first place.

What We're Actually Seeing in Kansas City

Go walk down any suburban development built in the last 30 years. Start digging at the base of a maple, redbud, or pin oak. If you can even find the root flare without a mini-excavator, you’re already ahead. Nine times out of ten, the root flare is buried — and not by nature. It’s buried by volcano mulching, landscape fabric, excessive fill dirt, and 'professionals' who couldn’t tell the difference between a root collar and a collarbone.

To make matters worse, these trees are typically:
- Planted too deep.
- Watered poorly.
- Installed with circling or pot-bound root systems.
- Left without staking, or worse, staked with wire cutting into bark.
- Smothered by grass, plastic edging, and rock mulch — all while expected to thrive.

Girdling Roots: A Symptom of Deeper Problems

Let’s go back to Holmes’ study. It showed different species had different tolerance levels. Even that tolerance is influenced by root vigor and trunk expansion — both of which are directly influenced by soil conditions, planting method, and water availability.

So yes, girdling can kill trees. But girdling roots form because of:
- Pot-bound roots never teased out.
- Poorly amended backfill.
- Poor irrigation.
- Compacted, anaerobic soil.

What the Old-School Experts Would Say

If the experts behind those 1980s girdling root studies could see the state of nursery stock, planting techniques, and watering practices today, they’d be appalled — and rightfully so. They assumed the tree had been planted decently in the first place. Imagine their reaction if they knew that most of today's urban trees are installed with the roots already circling in the pot, buried too deep, and often left to either drown or thirst.

These researchers had to fabricate synthetic girdling roots. Today, we don’t need artificial devices — the damage is built in at the nursery, at the jobsite, and with the hose. They’d be stunned to know most girdling roots weren’t the result of some rare fluke — but predictable outcomes of poor prep.

A Word on Watering: It’s Not Optional

Watering newly planted trees is not optional. Trees need consistent, deep watering for at least two years post-planting. Not sprinklers Without it, roots don’t establish, and they stay coiled in tight nursery spirals, eventually girdling the trunk. Where would the rots congregate with the system in the picture?

Real Solutions Start at Planting

Let’s make this standard practice:
1. Inspect nursery stock for circling roots.
2. Shave the root ball or box cut if needed.
3. Ensure visible root flare at the soil line.
4. Match soil conditions — no exotic mixes.
5. Use mulch properly: 2–4 inches deep, off the trunk.
6. Create irrigation plans with weekly deep soakings.

Final Thoughts: Let’s Stop Acting Surprised

Holmes and others offered insight, but when we encounter girdling roots, we must ask why they formed. And usually, the tree was doomed the day it was planted — too deep, with compacted roots and poor watering. That’s the real disease. Girdling is just one symptom.