The pohutukawa is the New Zealand Christmas tree, and the New Zealand pohutukawa is the New Zealand of trees, gnarled, salt-tolerant, spectacular in flower, slow to forgive bad pruning. If you have one on your section, particularly along the coast, here's how to keep it healthy and the right size.
When to prune
Avoid the flowering window, late November through to late January. Outside that, pohutukawa tolerate light shaping anytime. Major structural pruning is best done late autumn (March–May), when the tree is between flushes and you can see structure clearly.
Pruning during flowering doesn't kill the tree but you'll lose the show, and there's something a bit sacrilegious about it.
How much to take
The general arboricultural rule applies: no more than 25% of live canopy in a single year. Pohutukawa, being slow growers and significant flowerers, do better with less than that, 10–15% is usually plenty for an annual shape.
If you need to take significantly more than 25% (because the tree has outgrown its position over years of neglect), stage it across 2–3 years.
What to prune
- Deadwood. Coastal pohutukawa often have significant deadwood in the inner canopy, clear it.
- Crossing branches. Branches rubbing against each other create wounds; remove the lesser of the two at the trunk.
- Lift over driveways, paths, rooves. Pohutukawa naturally form low, spreading crowns, many residential trees need lifting.
- Crown reduction back to natural lateral branches if the tree has outgrown its space. Never top.
- Hanging aerial roots if they're a nuisance, but leave the ones at the trunk that buttress the tree.
The trap of topping
Pohutukawa do regrow from old wood, unlike most conifers, but the regrowth from topping is weak, vigorous and ugly. A topped pohutukawa loses its character forever. Reduction pruning back to laterals preserves the form.
Salt, wind & coastal pohutukawa
Coastal pohutukawa take a beating from salt spray and onshore winds. The crowns often look thin and weather-shaped, that's normal. Resist the urge to "fix" a salt-sheared canopy by heavy pruning; you'll usually make it worse.
Notable Tree status
Many large or significant pohutukawa are on council Notable Tree schedules, especially in Auckland, Bay of Plenty and Northland. Check before doing more than light maintenance. See our Notable Trees article.
Pests & problems
- Pohutukawa moth (Aenetus virescens): larvae bore tunnels into trunks. Usually cosmetic, but heavy infestations on stressed trees can cause limb failure.
- Possums: strip foliage and can defoliate young trees. Control is more about the broader environment than the individual tree.
- Myrtle rust (Austropuccinia psidii): a serious threat to the entire myrtle family including pohutukawa. Watch for yellow pustules on new growth. Report to Biosecurity NZ.