Monkey puzzle tree (Araucaria araucans) is an evergreen conifer tree native to mountainous regions of South America and grown as a unique landscape specimen in selected regions around the world. It has a much different look than most conifers. Now threatened by climate change, monkey puzzle tree is a very old species that has been present on earth since the time of the dinosaurs and is sometimes called a living fossil, it has a pyramidal shape with unusual 2-inch triangular leaves that cluster around upward-facing branches—even the trunk may be covered with these plate-like leaves. The foliage is not like the typically needle-shaped type. Instead, they are leathery, broad and dagger-like, and can remain on the tree for 10 to 15 years. As it ages, the tree loses lower branches, assuming an umbrella-like shape. The large 6-inch female cones take up to three years to ripen and disperse edible seeds, which have a taste similar to pine nuts.
Monkey puzzle tree is best planted as a nursery-grown container plant in the fall or spring. It is a slow-growing but very long-lived tree, taking a full 10 years to reach 20 feet in height. In the wild, it has been known to reach 80 feet in height, but garden trees usually reach a maximum of 20 to 30 feet.
|Common Name||Monkey puzzle tree, Chilean pine|
|Botanical Name||Araucaria araucana|
|Plant Type||Coniferous evergreen tree|
|Mature Size||50–80 ft. tall, 20–30 ft. wide|
|Sun Exposure||Full, partial|
|Soil Type||Semi-rich, evenly moist, well-drained|
|Soil pH||Acidic to alkaline|
|Hardiness Zone||7-10 (USDA)|
Monkey Puzzle Tree Care
Monkey puzzle tree is easy to grow in the right climate—but temperamental in many locations. Mediterannean-type climates at high elevations are ideal, but northern regions or areas where summers are quite hot will require just the the right site. Not every location within the zones 7 to 10 hardiness range will be suitable—only areas with fairly cool summers and mild winters, and areas without serious urban pollution issues. Although forgiving of different soil types, monkey puzzle tree requires a sheltered area that is protected from winds. In areas with hot summers, some afternoon shade is preferred.
Choose a spot well away from sidewalks and driveways, as this tree's surface roots have the potential for heaving paved surfaces. The planting hole should be twice as wide as the tree's nursery container, with soil that is well loosened. Plant it at the same height as it was growing in the container. It is always good to have a helping hand to make sure your tree is completely straight as you fill the soil back into the hole. Then, place 2 to 3 inches of mulch around your tree without it touching the trunk. You may want to stake your tree to ensure strong winds do not displace it.
After planting, soak the tree thoroughly and water it weekly with long soaks that drench the entire root system. Less frequent deep watering is better than more often shallow watering. Once the tree is established, it usually survives nicely on ambient rainfall.
Monkey puzzle trees want full sun but will tolerate partial shade, especially in hotter regions. They do not tolerate deep shade. If growing in a container, make sure the window gets plenty of direct light.
One real positive about growing the monkey puzzle tree is that it will tolerate a wide range of soils providing they are deep and the drainage is good. In a container, adding some perlite to the potting mix may aid drainage.
If the tree has established itself and you have watered it well for the first year or two as instructed above, then watering your monkey puzzle is low maintenance. The tree prefers medium moist soil and that can usually be maintained by the precipitation that occurs naturally. If a dry spell does occur, water as needed. For a plant in a container besides keeping the soil moist, a regular misting will be needed.
Temperature and Humidity
The official hardiness range for the monkey puzzle tree is USDA zones 7 to 10, but it is borderline in warmer regions and does not tolerate dry weather. It can survive brief temperatures down to minus 4 degrees Fahrenheit.
If your garden is dry or can reach colder temperatures, consider growing in a pot that can e moved back and forth between outdoor and indoor locations as the seasons shift.
The monkey puzzle tree does not need supplemental feeding, thriving nicely on the nutrients provided by any type of soil.
Types of Monkey Puzzle Tree
While there are cultivars available for this tree, they are of most interest to collectors and arboretums. The tree normally available for sale in the horticulture trade is the pure species.
Monkey puzzle trees generally require no pruning, other than to remove dead or broken branches. These should be removed all the way back to the main trunk, as partial pruning often kills the entire branch.
These trees are "self-pruning" as they age—lower branches die and fall off, creating a tree with an eccentric upper canopy.
Propagating Monkey Puzzle Tree
Monkey puzzle tree is very hard to propagate by vegetative means, so it is normally done by collecting and planting seeds (see below).
How to Grow Monkey Puzzle Tree From Seed
Although growing a monkey puzzle tree from seeds is not particularly hard, you will need to either purchase the seeds or obtain them from someone who has a mature tree, as the cones do not begin producing viable seeds until the tree is 40 to 50 years old.
Purchased seeds are the better option because you will be assured that they are female seeds. If collecting from mature cones on an existing tree, the female seeds will be fat and plumb rather than the thin and flat shape of the male seeds.
Soak the seeds in water overnight, then plant in seedling flats filled with potting mix with the pointed tops facing down and the tops exposed. Place under a plastic cover and place the flat in a sunny window. They require temperatures of 68 degrees Fahrenheit in order to germinate. Keep the potting mix moist but now soaking until germination, which can range from a few weeks to two months. When the seedlings are large enough, they can be transplanted into individual pots. It is typical to grow them in pots for or three years before transplanting them into the garden.
Potting and Repotting Monkey Puzzle Tree
Like its relative, Norfolk pine, monkey puzzle tree is sometimes grown as a container plant in regions where it cannot survive winters outdoors. In cooler climates, it is best to give it plenty of outdoor time during the summer, moving it indoors only for the winter. Because these plants are native to mountainous regions near the equator, they need lots of light, and this can be hard to achieve during winter months in northern regions with short days. Providing auxiliary lighting may be necessary. This plant can be hard to grow as a permanent indoor houseplant.
Monkey puzzle trees should grow well enough in any well-draining potting mix in a pot with good drainage (any pot material will do). Every few years when roots begin poking out of the drainage hole, repot the plant into a larger container with fresh potting mix.
It's a good idea to periodically flush the pot with heavy watering to flush out mineral salts. Other than this, keep the potting mix moist but not wet.
When grown in its established hardiness range, monkey puzzle tree requires no protection against winter cold. Gardeners in cold-winter regions who are growing it as a container plant should move it indoors as temperatures begin to dip below freezing. For the winter months, a potted tree will need as much light as you can give it.
Common Pests & Plant Diseases
Monkey puzzle tree is generally resistant to pests and diseases, but there can be occasional problems with scale, mealybugs, thrips, and spider mites. Neem oil or another horticultural oil are good remedies.
Leaf spot, sooty mold, and phytophthora root rot are among rare but possible disease issues. Mold and leaf spot are usually not fatal and are easily treated with fungicides, but once root rot takes hold, it will likely kill the tree. Poorly draining soils and overly wet conditions encourage these mold and fungal diseases.
Common Problems With Monkey Puzzle Tree
Homeowners sometimes come to lament the messiness of monkey puzzle tree, which can drop large quantities of large, hard cones in the fall once the tree is mature, often assualting pedestrians walking below. Large trees with substantial surface roots can also heave sidewalks, driveways, and patios. This tree can get surprisingly large, so it should be planted with at least 24 feet of open space around it. Don't plant this tree near overhead utility lines.
Owners are sometimes surprised when the tree begins to shed its lower branches as it gets older. This is entirely natural.
How did this tree earn its common name?
The monkey puzzle tree is a coniferous gymnosperm with a wildly unusual look that is the origin of its equally odd name. According to the popular story, a member of the English parliament, Sir William Molesworth, was having a luncheon with some friends at his country home, and while showing his garden, his friend, the famous lawyer, Charles Austin, said of the tree, "It would puzzle a monkey to climb that." Having no common name at that point, the name stuck.
Is this species formally protected?
Although the fossil records indicate that this species once covered a vast area of South America, Africa, India, and Austrailia, today it can only be found in a very small tract of land in the rainforests and coastal mountains of Chile. It is now a protected tree by CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora), and has been named the national tree of Chile.
How is this tree used in the landscape?
Monkey puzzle tree has never naturalized in the U.S., due to its limited hardiness range and unique requirements. But it can make an interesting specimen tree in some areas of the South, Southwest, and West Coast of the U.S. Because its native enivronment includes coastal regions, the tree has developed excellent salt tolerance.
How long does monkey puzzle tree live?
Human-set fires, forestry, and the introduction of new species of animals have led to the monkey puzzle tree’s recent demise. The tree takes up to 40 years to produce cones and is incredibly long-lived—up to 1200 years. Often the trees do not live long enough to reach an age where cone production is possible, therefore the next generation does not continue.
Can I eat the seeds?
Yes. The seeds found within the mature cones on this tree have a taste similar to pine nuts, but are soft like cashews. These nuts make the tree quite appealing to birds and other animals.