The monkey puzzle tree Araucaria araucana is an endangered species in its native Chile, but has thankfully become more and more common as an ornamental tree in the southern United States, in Britain and in Europe. I love it because of its uniqueness – particularly when young it has a skeletal, highly symmetrical habit that provides interest all year round.
However if you’ve ever seen a brown branch tip (or whole branch!) on a monkey puzzle, you may be left wondering what’s gone wrong. Why is it turning brown?
Monkey puzzle trees’ lowest branches naturally turn brown as they age. While they eventually will be shed, these branches can be pruned to maintain the tree’s symmetry. Other reasons for brown foliage include drought, recent transplanting and excessive shade.
While I’ve always been around these trees, I wondered what factors might influence their health. I’ve learned a lot more about them lately after doing some intensive study within my library of tree books and journals! I hope to unpack it in a digestible form and bring you accurate, scientific but practical (hands-on!) info!
Where does the monkey puzzle tree get its name? Well, according to a historical article in the Financial Times, it’s said that the barrister Charles Austin (1799-1874), upon seeing a specimen in the garden of Sir William Molesworth in Cornwall, England, exclaimed that to climb one “would be a puzzle for a monkey”. The name somehow stuck.
Why is my monkey puzzle tree turning brown?
Let’s break this down into young (<20 foot) and older monkey puzzles.
Younger monkey puzzle trees turning brown
A seedling monkey puzzle usually won’t display the classic lower-down brown branches until it’s much older. It usually turns brown because of one of the following factors
This tree is moderately drought tolerant, but as with most evergreens, it’s particularly exposed to the effects of dry soil when it’s young and doesn’t have a well-developed root system. Moreover, many spend time in containers in their first years, and are often left in a bit too long – when lifted out, the roots are often ‘girdling’ – circling the inside of the pot. The young tree can’t survive this forever and needs planted or moved to a bigger pot.
Keep the roots of your monkey puzzle from drying out frequently. Usually this amounts to a small amount of water for a pot-bound plant each week – enough to keep the soil moist – but if the tree’s outside, you can usually reduce the watering frequency to every 4-6 weeks in the winter as long as the pot’s in a spot well sheltered from wind and frost.
You can also apply some organic mulch, such as bark chippings, around the base of the tree. This helps water permeate into the roots, and insulates them from extreme temperature changes.
A container-bound monkey puzzle should usually be planted out eventually. You can do this from late autumn to early spring. This enables it to develop its usual deep taproot (as well as spreading surface roots) that help it gain both stability and gives it a bit more protection from drought.
Where to plant it out in the first place, and what do you need to consider before you do? More on that below!
b) Recent transplanting
This naturally brings us to the issue of moving the monkey puzzle tree either from pot to ground or from one part of your property to another. Have you done this in the past three years? This can actually be the thing that makes the tree turn brown.
The term ‘transplant shock’ is often used to describe the near-death experience that trees and plants go through when they’re moved. A sudden upheaval followed by a change in temperature, soil composition, moisture, nutrients, and sunlight is made worse by the fact that roots are often damaged or altogether severed during the process. Transplant shock is common in many trees, including other evergreens such as pine, spruce, cedar and hemlock.
In such cases you may see the sharp tips of the monkey puzzle – the parts that are actively growing – suffering first, looking desiccated and brown, as the roots struggle to transport water to them.
Monkey puzzles will usually survive this process – but if every part of the tree’s turning a shade of brown, it may be a sign that it’s dying.
The best remedy is to keep the roots really well watered for the first year after transplant. Start this if you can before you actually plant it by giving the roots a proper soak, then water it weekly – just avoid waterlogging the soil – you’re going for damp, not sodden. This will compensate for the temporary nosedive in water uptake from the roots.
And again, applying mulch around the base (2-3 inches thick, at least as far out as the foliage extends) will help water get into the soil and also prevent too much evaporative loss from the sun.
While monkey puzzles will usually tolerate clay soil, the actual transplant into clay soil can be a tricky time. Often a basin in the ground is dug out to pop the tree into, but the insides of that hole are ‘glazed’ after much scraping with a spade – shiny, like walls of thick clay. The roots of the young tree have difficulty breaking through this barrier, and can continue circling as if in a pot.
The remedy here it to break up and turn the soil in a much larger radius – usually 2 feet in every direction will do – or if that’s not possible, at least slice into the sides of the planting hole well with your spade before putting the tree in.
c) Excessive shade
I’ll put this in the ‘young monkey puzzle’ section as your tree likely won’t make it to maturity if you try to grow it in a shady spot. They usually need full sunlight to thrive. Shaded specimens grow slowly, lacking their graceful form, and will get excessive brown branches – probably the lowest ones first.
In my opinion, an unobstructed sunny spot suits the monkey puzzle tree’s look anyway – they need plenty of room and display themselves best on a stand of their own, rather than surrounded by other trees.
d) Changes in the tree’s environment
Sometimes changes in the tree’s surroundings can simulate the impact of drought on a monkey puzzle. For example, I’ve heard of trees turning totally brown after an area close to them was paved or surfaced. This essentially cuts off all water to a proportion of the roots. If you’ve done this, be prepared to water your tree more often to make up for it.
Some think that monkey puzzles are popular for dogs to pee against. Goodness knows why, as they’re so spiky. But if you have one that’s doing poorly or turning brown, it might be worth keeping a look out for that problem, as it alters the soil pH and composition.
According to the famous tree expert F. Bayard Hora, air pollution makes the tree lose its lower branches at an earlier stage.
Older monkey puzzle trees turning brown
Have you ever noticed that young Araucaria araucana have branches right down to the ground, while mature ones may have a long clean trunk? Monkey puzzle trees do normally go through a process where their lowest (oldest) branches turn brown and eventually dropping off, which leaves the trunk bare on the lower half. However this is an extremely slow and gradual process, and gardeners can safely prune off the branches once they’ve turned brown to keep the tree looking tidy.
It’s common to see the branches falling off in a somewhat assymetrical fashion, particularly if they are more shaded or have less room to grow on one side, which spoils the look somewhat.
As another example, have a look at this mature monkey puzzle outside a bar in Wales, UK (Google Streetview link). The spots on the trunk reveal where old branches have now fallen off, and note how the building’s proximity has meant fewer branches have been preserved on that side.
It’s not hard to prune off branches that are very low down – just cut close to the trunk but leave the ‘branch collar’ where the branch connects to it. But in tall mature monkey puzzles it can prove a challenge particularly as the spiky branches can be quite threatening as they fall – so consider an expert for this job.
Could a disease be affecting my monkey puzzle tree?
It’s not outside of the realms of possibility, but monkey puzzle trees are pretty darn resistant to disease and pests, which may be one of the reasons they’ve stuck around for 200 million years (they once formed a major part of herbivorous dinosaurs’ diet. Some scientists suggest the sharp spiny leaves developed to try to fend them off!).
While they’re resilient, they can get occasionally suffer from:
- sooty mold (grimy grey mold on the leaf surface – spray with neem oil)
- spider mites infestation (watch out for webs and yellow dots on leaves – need oil again or hose them off regularly)
- And honey fungus (the most serious, causing general dieback and browning, spitting bark with white growths between bark and wood).
If you’re suspecting honey fungus, definitely get an arborist in – usually the tree will have to be removed and disposed of. It can be quite advanced by the time these signs show up, as it begins underground.
Fertilizing monkey puzzle trees
Will fertilizer help? It might. While most well-established Araucaria araucana have become accustomed to their soil and surroundings, younger trees or those that are growing poorly may benefit from the addition of a slow-release complete fertilizer such as Miracle-Gro’s Tree & Shrub spikes or Jobes Evergreen Fertilizer Spikes. I love how easy these are to use. The slow-release element stops gardeners from overdoing it and means the tree always has ready access to what it needs.
How big will my monkey puzzle tree get?
Monkey puzzle trees have two distinct forms – it completely changes shape as it ages. Have a read at my article where I’ve heavily researched and answered this in detail.
I hope you’ve enjoyed this article. Please take a look at my other posts!
Hummel J, Gee CT, Südekum KH, Sander PM, Nogge G, Clauss M. In vitro digestibility of fern and gymnosperm foliage: implications for sauropod feeding ecology and diet selection. Proceedings of the Royal Society B: Biological Sciences. 2008 May 7;275(1638):1015-21.
F. Bayard Hora. The Oxford Encyclopedia of Trees of the World. Oxford University Press, 1981.
Mike Pennington / Monkey Puzzle (Araucaria araucana), Royal Botanic Gardens, Edinburgh
Lynn M Reid / Baby Monkey Puzzle Tree In Barbour Cemetery
LightPhoenix, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons