Monkey puzzle tree: growth rate, size (and what to consider) | Hands-On Gardening (2024)

There’s a bit of an obsession around where I live with planting monkey puzzle trees in front gardens. I admit I love them when they’re young, when they sure do get rather big! A neighbor was a bit shocked when I told her Araucaria araucana can live to well over a thousand years old…

If you have one of these trees on your property or are thinking of planting one, you really need to know what to expect. Remember the phrase “plant the right tree in the right place”. As always, my aim’s to bring you accurate and trustworthy information from my own experience and a variety of the most reputable sources – particularly my library of tree books!

How fast do monkey puzzle trees grow?

While they’re slower in their first 5 years, monkey puzzle trees can be expected to gain height by around 1 foot (30cm) per year, or at most 2 feet (60cm) in the best conditions. A 10-year-old specimen will typically be around 6m (20 feet) tall and with a spread diameter of 3m (10 feet).

How big do monkey puzzle trees get?

The world’s tallest monkey puzzle tree grows in its native Chile. ‘Araucaria Madre’ is 51m (167 feet) tall and estimated to be 1,800 years old. The tallest known specimens outside of Chile are approximately 30m (98 feet) tall and date back to the mid-1800s when the tree was first cultivated abroad.

Like other ancient evergreens such as the giant sequoia, while young they adopt a conical ‘Christmas tree’ shape, but when they’re older they’re more columnar and don’t spread out a lot more – instead putting on height (check out my in-depth article on growing the fascinating giant sequoia here).

Araucaria araucana branches typically spread out to a maximum of 10 meters (33 feet) in diameter in their first 100 years, with the largest ones sticking to around 15 meters (49 feet).

Here’s a chart to help you envisage what your monkey puzzle tree’s likely to approximate to, height and size-wise, in the years to come – if you already have one of these trees, it may help you estimate how old it is.

A 2-story house is about 20 feet tall, so you can expect this tree to greatly outsize your house in your lifetime. Think carefully then, before you plant! This is a wonderful ornamental – but it’s one to grow out on its own in the middle of a large space.

Where is the best place to plant a monkey puzzle tree

Monkey puzzle trees require full sun and soil that drains well. So don’t bother planting it in a shady spot, or in a marshy bit of lawn. It will never grow well, and will likely lose its lower branches early, resulting in an unhappy-looking, slow-growing specimen.

Think ahead – don’t plant under power lines or you’re going to have a problem one day. This isn’t a tree for a small garden.

Plant it out on its own, on the sunny side of your property in an open spot.

How close to a house can I plant a monkey puzzle tree?

As a general rule, plant monkey puzzle trees at least 8m (26 feet) away from a building. This allows for the symmetrical spread of branches (5-7m from the trunk in the fully grown specimens).

You may see specimens that are planted much closer, but the building can limit the symmetrical growth of the tree (and of course, the reason we’re growing it is for its beautiful ornamental form!) – again take a look at this UK Google Street View image from a little further out. It looks barely 2m from the pub and has developed a rather lopsided habit.

Do monkey puzzle trees have invasive roots? How far do they spread?

Monkey puzzle trees have both a downward taproot and shallow surface roots that spread out father than the foliage above. While the surface roots can lift pavement and feasibly could invade drainage systems, being so close to the surface it is rare for them to cause serious structural damage.

The deep downward taproot is said to go down about half as far as the height of the trunk (though I think there’s a paucity of actual data on this, probably owing to how difficult it would be to completely dig the root out and measure it!).

I’ve never heard of these trees causing problems with foundations, and on a deep dive online through various forums I wasn’t able to find any cases of tree owners having sustained structural damage as a result of the roots.

That’s not to say it could never happen though. These trees can live over 1000 years – so can certainly outlive your house. A safe option is to check with your home insurance company whether allowing Araucaria araucana to grow close to your property would affect your cover.

Can you keep a monkey puzzle tree small?

It is possible to limit their size when they’re still small, but it’s difficult to do. Aside from being a very prickly character to deal with, you’d have a difficult time keeping it growing symmetrically and in that shapely conical form. You could do this during the winter months, but for the aforementioned reasons, it’s better left unpruned.

Really, it isn’t practical in my view. The worst thing you see (in my opinion) is ‘topped’ monkey puzzles, which look like a Christmas tree with the top chopped off.

It is OK to ‘limb up’ and remove any uneven, brown or dying lower branches though. Here’s my article on the causes of dead and dying branches on a monkey puzzle tree.

Of course you could grow your tree in a pot, which, in limiting the size of the root ball will suppress the upward growth as well. But this, effectively, is limiting the lifespan of the tree as well, as the roots will eventually girdle (circle around the inside of the container) until you either move it to a bigger container or plant it out.

When do monkey puzzle trees produce seeds?

Monkey puzzle trees may not produce trees for at least 10 years.

They’re edible though, and particularly tasty when roasted. They grow inside very large (15-20cm long) coconut-shaped spiny green cones of the female tree, which mature every 2-3 years.

Fortunately, when the seeds are ripe, the cone breaks up while still on the branch and the seeds shower down to the ground, so it’s not normally known for falling intact on people’s heads (but the risk of that is something I’d rather be aware of if I was sitting under a mature tree).

The male cones are only 10cm long and slimmer. Monkey puzzles tend to be either female or male (dioecious).

A closely related tree, the bunya pine (Araucaria bidwillii) does drop its cones intact – and they’re up to a foot in maximum diameter, so watch out!

Like other evergreens, the number of cones can vary throughout the monkey puzzle tree’s lifetime. I wrote an article about why this happens.

Just a little addendum if you’re interested…

Why are they called monkey puzzle trees?

Where does the monkey puzzle tree get its name? Well, according the 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.

Which only begs the question:

Can monkeys actually climb monkey puzzle trees?

I really wanted to know the answer to this one. Having wasted too long trawling the internet I have yet to find documentary evidence of a monkey climbing a monkey puzzle tree.

Interestingly, squirrels apparently can’t – making a monkey puzzle a good place to hang a bird feeder.

Humans can climb ’em though, with a couple of ropes…

One more….

How do I make a monkey puzzle tree grow faster?

You can do this by keeping it in ideal conditions – and for more on this, read my article about monkey puzzle problems that you’ll need to avoid!

Photograph attribution: Dingwall: monkey puzzle tree byMartyn Gorman, CC BY-SA 2.0 https://creativecommons.org/licenses/by-sa/2.0, via Wikimedia Commons

Richard Avery, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons