How Far Apart to Plant Trees

Space on the size it becomes

A tree four feet across in the pot may finish at twenty-five.

That's the whole problem. The spacing that feels comfortable on planting day is almost always too tight, and by the time it's obvious the tree has already lost its shape on the crowded side. The remedies at that point are removal, or a lifetime of corrective pruning.

Plant for the tree you'll have. If the gaps look bare meanwhile, fill them with something short-lived you're genuinely willing to take out.

The arithmetic, once you have the spread

Each tree needs half its own canopy between its trunk and the point where the two crowns meet. Half of one plus half of the other is the average — so:

Distance between trunks = (spread A + spread B) ÷ 2

Two 20 ft trees want 20 ft between trunks. A 30 ft tree beside a 10 ft one also wants 20 ft, which surprises people but follows directly.

Anything you want between them — room to walk, room to mow, light reaching the ground — is added on top. That's why Gap you want between mature canopies is separate rather than folded in.

Where the spread comes from — not from here

Mature spread is an input, and deliberately so. It varies by species, by cultivar, by rootstock and by conditions. The same apple on a dwarfing rootstock and on a vigorous one finish at very different sizes.

The figure is on the nursery tag or in the supplier's catalogue. A local grower or your extension service often knows how a species actually behaves in your area, which beats a catalogue range written for a whole country.

A calculator guessing this would be wrong by a factor of several, which is why it asks.

Touching isn't always wrong

The tool doesn't force a gap, because it depends what you're planting.

• A windbreak, hedge or screen is supposed to close up. The point is a continuous barrier, so you plant tighter than the touching distance on purpose.
• An orchard or a specimen tree is the opposite — each wants its full crown, light all round, and access to pick and prune.

Decide which you're planting before you decide the spacing. The same species belongs at genuinely different distances in the two cases.

The wall clearance is about branches, not roots

This is the most important limitation on the page.

Trunk distance from a wall is half the mature spread plus your clearance. It keeps branches off the building and gives you room to get past.

It says nothing about roots. Roots typically extend well beyond the canopy, and they're the half of the tree that argues with drains, foundations and paving. The distance that matters there is set by your local rules, your utility company and sometimes your insurer — and on shrinkable clay it can be considerable.

Check those before digging. This figure doesn't substitute for them.

Look up, and look down

Required clearances near overhead lines have nothing to do with canopy width and everything to do with your utility company's rules. A tree planted under a line is one that will be cut badly for the rest of its life — repeatedly, by someone whose job is clearance rather than shape.

Walk the site and look up before choosing positions. Locate underground services on the same trip.

Fitting a run

Trees that fit along the run assumes a tree at each end, which suits an avenue across open ground.

If the run is bounded — a fence, a wall, a neighbour's boundary — set the end trees in by half their mature spread so they're not overhanging it at maturity, and take one off the count.

Spare length at the end of the run is what's left over after the last tree. Spread it across the gaps rather than dumping it all at one end; a row with one visibly wider gap reads as a mistake even when the spacing is right.

And for a block

Ground each tree gets and Trees per acre on a square grid are there for an orchard or a woodland planting. An acre is 43,560 sq ft, so 20 ft spacing gives about 109 trees — and adding a 10 ft gap drops that to 48. Spacing costs land quickly, which is worth seeing before ordering stock.