Commercial Tree Planting and Establishment

Choosing a tree that will still be right in 2060

Almost every problem tree on a commercial property today was planted by somebody making a reasonable decision with the information they had. The main thing that has changed is that we know more about mature size and root behaviour.

Two questions do most of the work. How big does this species actually get, above and below ground, and does the space have room for that. Not the space it has now, the space it will have when the building next to it is still there in forty years.

The second question is what it drops and where. A tree that drops seed balls, heavy flowers, or fruit is fine over turf and a permanent problem over a walkway or a parking stall.

Planting depth is the thing most often wrong

More newly planted trees are killed by planting depth than by anything else, and the damage is invisible for years.

A tree planted too deep buries the root flare. The trunk sits in moist soil, which it is not adapted to, and roots circle rather than spreading. The tree survives, grows slowly, and declines a decade later for reasons nobody connects to the day it went in.

The correct depth puts the root flare at or slightly above finished grade. The hole should be wide rather than deep, two to three times the root ball across, with the sides roughened so roots can leave rather than circling in a smooth walled hole.

Do not amend the backfill heavily. A rich pocket in poor soil encourages roots to stay inside it rather than spreading into the surrounding ground.

1. Dig wide, two to three times the root ball, and no deeper than it
2. Roughen the sides of the hole so roots can penetrate
3. Set the root flare at or slightly above finished grade
4. Backfill with native soil rather than a rich amended mix
5. Water in thoroughly to settle the soil rather than tamping hard
6. Mulch a wide ring, pulled back from the trunk

The first three years decide the next forty

A newly planted tree has almost no root system relative to its canopy. Until that changes, it depends entirely on being watered, and that period lasts two to three years rather than a season.

The most common failure is cutting water at the end of the first summer, because the tree looks established. It is not. It is surviving on a root ball that has barely spread.

Stakes are the second issue. They are there to hold the root ball still while roots anchor, not to hold the trunk upright forever. Left on, ties girdle the trunk and the tree never develops the trunk taper that comes from moving in wind. Off within a year is the rule.

The third is the mulch ring, which keeps mowers and string trimmers away from a young trunk. Trimmer damage at the base is a common and entirely avoidable cause of young tree failure.