Planting a tree so it lives
Wide hole, not deep. Stake low, not high. Water through the second summer, not just the first.
Wide, not deep
The single most common fatal mistake is planting too deep. The root flare, where the trunk widens into the roots, must sit at or very slightly above the finished soil level. Buried, the bark stays permanently wet, it rots, and the tree declines over several years in a way nobody connects to the planting.
The hole wants to be two to three times the width of the root ball and no deeper than it is tall. Loose soil under a root ball compacts and the tree settles, which buries the flare after the fact. Firm ground underneath, loosened soil all around.
- Root flare at or above soil level
- Never buried. Buried bark stays wet and rots, and the tree declines over years.
- Two to three times as wide
- Roots spread sideways into loosened soil. Width is what a new tree uses, not depth.
- Never deeper than the root ball
- Loose soil beneath compacts and the tree sinks, which buries the flare afterwards.
- Do not dig a pot shape
- Break up the sides. A smooth walled hole in clay is a sump that roots will not leave.
What to do with the roots
A container grown tree usually has roots circling the pot, and those will keep circling once planted and eventually strangle the trunk. Tease them out straight, and cut through any that are badly spiralled. It feels destructive and it is the right thing to do.
A bare root tree should go in while dormant and must not dry out for even an hour before planting. Keep the roots covered and damp until the moment the tree goes in the hole, because bare roots die from wind and sun faster than from anything else.
- Uncircle container roots
- Tease them straight and cut the badly spiralled ones. Left circling they strangle the trunk.
- Never let bare roots dry
- Covered and damp until the moment it goes in. Wind and sun kill exposed roots within the hour.
- Plant bare root while dormant
- Late autumn to early spring. Bare root in leaf almost never establishes.
- No fertiliser in the hole
- It encourages roots to stay in the enriched pocket rather than spreading into the surrounding soil.
Stake low, and remove it
A stake exists to stop the root ball rocking while the roots take hold, not to hold the trunk upright. So it goes low, about a third of the tree's height, with a single tie at the top of the stake. Staked high, the trunk cannot flex, and a trunk that never flexes never thickens or strengthens.
The stake comes out after one or two growing seasons. Left on, the tie girdles the trunk as it thickens and the tree either snaps at that point or dies. Forgotten ties are one of the most common causes of loss in young street and garden trees.
- A third of the height, no more
- The stake holds the roots still. The trunk needs to flex in order to thicken and strengthen.
- One tie, at the top of the stake
- With a spacer so the trunk does not rub. Two ties immobilise the trunk entirely.
- Stake outside the root ball
- Driven in before the tree goes in, or angled. A stake through the root ball damages roots.
- Remove after one or two seasons
- A forgotten tie girdles the trunk as it thickens. This kills a great many young trees.
The second summer is the one that kills them
Almost everyone waters a new tree through its first summer and stops. The second summer is when it dies, because the roots have not yet reached beyond the planting hole and the tree is carrying much more leaf than it was.
A young tree needs a genuine soak, meaning 20 to 50 litres, weekly through dry weather for two growing seasons. Light frequent watering is worse than none, because it keeps the roots shallow and in the top 50mm where the soil dries out first.
- Two summers, not one
- The second is when a well planted tree most often dies, and it is the one people skip.
- 20 to 50 litres, weekly
- A real soak. Light frequent watering keeps roots shallow, which is worse than not watering.
- Water the root ball
- Not a wide circle. For the first two years the roots are still where the pot was.
- Mulch, but not against the trunk
- 75mm of mulch in a ring, kept clear of the bark. Mulch piled on the trunk rots it.
Protection and the mower
Rabbits, deer and voles will strip the bark off a young tree in a winter, and a ring of bark removed all the way round kills it outright. A spiral guard or a mesh sleeve costs very little and prevents the commonest form of total loss.
The other threat is a strimmer. Nylon line strips bark faster than any animal, and the damage goes unnoticed because it is at ground level. A mulched circle around the tree means nothing needs to be cut close to it at all.
- Guard against bark stripping
- Rabbits and voles ring a young trunk in one winter, and a ringed tree is dead.
- Keep strimmers away entirely
- Nylon line strips bark at ground level where nobody looks. A mulch circle removes the need.
- Check guards do not constrict
- A spiral guard left on too long does the same thing a forgotten tie does.
- Deer need height
- A short guard is useless against deer. Match the guard to what is actually in your area.
Frequently asked questions
- What tools do I need to plant a tree?
- A spade, a garden fork, a wheelbarrow, a stake and mallet, a tree tie, a watering can or hose, and mulch. Add a planting bar or mattock for hard or stony ground and a guard if rabbits or deer are present. Most of the tool list is short and the technique is what matters.
- How deep should I plant a tree?
- No deeper than the root ball is tall, with the root flare where the trunk widens into the roots sitting at or very slightly above finished soil level. Planting too deep keeps the bark permanently wet so it rots, and the tree declines over several years.
- How wide should the planting hole be?
- Two to three times the width of the root ball, with the sides broken up rather than left smooth. New roots spread sideways into loosened soil, so width is what a young tree uses. A smooth walled hole in clay acts as a sump that roots will not leave.
- How should I stake a new tree?
- Low, at about a third of the tree's height, with a single tie at the top of the stake and a spacer to stop rubbing. The stake stops the root ball rocking, not the trunk swaying, and a trunk that cannot flex never thickens properly.
- When should I remove a tree stake?
- After one or two growing seasons. Leaving it on is actively harmful: the tie girdles the trunk as it thickens and the tree snaps at that point or dies. Forgotten ties are one of the most common causes of loss in young trees.
- How much should I water a newly planted tree?
- A genuine soak of 20 to 50 litres, weekly through dry weather, for two full growing seasons. Light frequent watering is worse than none because it keeps the roots shallow. The second summer matters most and is the one people stop watering in.
- Should I add fertiliser or compost to the planting hole?
- Generally no. An enriched pocket encourages roots to stay in it rather than spreading into the surrounding soil, which leaves the tree poorly anchored and dependent. Improve a wide area if the soil is very poor, rather than filling the hole with something better.
- When is the best time to plant a tree?
- Autumn to early spring while the tree is dormant, so it establishes roots before it has to support leaf. Bare root trees must be planted in that window. Container grown trees can go in at other times but will need much more watering if planted in summer.
