Monkey Puzzle (Araucaria araucana)

Chilean Pine, Chile Nut, Chile Pine, Monkey Puzzle, Monkey Puzzle Tree, Monkeypuzzle Tree, Monkey Tail Tree, Parana Pine, Pehuen, Pewen, Pinonero

Monkey puzzle tree is distinctly known for its unique physical features having tiny and spiky leaves. It produces cones that are feasted on by birds and squirrels. Its common name was derived from a comment that its appearance is as unique as it appears to be challenging for a monkey to climb.

I. Appearance and Characteristics 

Araucaria araucana, commonly called the monkey puzzle tree, monkey tail tree, piñonero, pewen or Chilean pine. It is native to central and southern Chile and western Argentina. It is the hardiest species in the conifer genus Araucaria. Because of the prevalence of similar species in ancient prehistory, it is sometimes called a living fossil. It is also the national tree of Chile. Its conservation status was changed to Endangered by the IUCN in 2013 due to the dwindling population caused by logging, forest fires, and grazing.

The leaves are thick, tough, and scale-like, triangular, 3–4 cm (1+1⁄4–1+1⁄2 in) long, 1–3 cm (1⁄2–1+1⁄4 in) broad at the base, and with sharp edges and tips. According to Lusk, the leaves have an average lifespan of 24 years and so cover most of the tree except for the older branches.

It is usually dioecious, with the male and female cones on separate trees, though occasional individuals bear cones of both sexes. The male (pollen) cones are oblong and cucumber-shaped, 4 cm (1+1⁄2 in) long at first, expanding to 8–12 cm (3–4+1⁄2 in) long by 5–6 cm (2–2+1⁄2 in) broad at pollen release. It is wind pollinated. The female (seed) cones, which mature in autumn about 18 months after pollination, are globose, large, 12–20 cm (4+1⁄2–8 in) in diameter, and hold about 200 seeds. The cones disintegrate at maturity to release the 3–4 cm (1+1⁄4–1+1⁄2 in) long nut-like seeds.

The thick bark of Araucaria araucana may be an adaptation to wildfire.

The tree’s native habitat is the lower slopes of the Chilean and Argentine south-central Andes, typically above 1,000 m (3,300 ft). In the Chilean Coast Range A. araucana can be found as far south as Villa Las Araucarias (latitude 38°30′ S) at an altitude of 640 m asl. Juvenile trees exhibit a broadly pyramidal or conical habit which naturally develops into the distinctive umbrella form of mature specimens as the tree ages. It prefers well-drained, slightly acidic, volcanic soil, but will tolerate almost any soil type provided it drains well. Seedlings are often not competitive enough to survive unless grown in a canopy gap or exposed isolated area. It is almost never found together with Chusquea culeou, Nothofagus dombeyi, and Nothofagus pumilio, because they typically outcompete A. araucana.

II. How to Grow and Care

Sunlight

Monkey puzzle trees want full sun but will tolerate partial shade, especially in hotter regions. They do not tolerate deep shade. If growing indoors in a container, place the plant near a window that gets plenty of direct light.

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 the tree in a pot that can be moved back and forth between outdoor and indoor locations as the seasons shift.

Watering

If the tree has established itself and you have watered it well for the first year or two, as instructed above, 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. 

Soil

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. Adding some perlite to the potting mix in a container may aid drainage.

Fertilizing

The monkey puzzle tree does not need supplemental feeding, thriving nicely on the nutrients provided by any type of soil.

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 best option because you will be assured that they are female seeds. Monkey puzzle trees are dioecious, meaning that male and female cones appear on separate trees. Male cones are elongated and oval, while female cones are large and round. If collected from mature cones on an existing tree, the female seeds will be plump and rounded rather than the thin and flat shape of the male seeds. If you collect seeds, make sure to sow them right away.

  • Soak the seeds in water overnight, then plant in seedling flats filled with potting mix with the pointed tips facing down and the tops exposed.
  • Cover with plastic and place the flat in a sunny window. The seeds require temperatures of 68 degrees Fahrenheit to germinate.
  • Keep the potting mix moist but not soaking until germination, ranging from a few weeks to two months.
  • When the seedlings are large enough, you can transplant them into individual pots. Grow them in pots for about three years before transplanting them into the garden. Make sure to harden off the plants before planting them outside.

Pruning

Monkey puzzle trees generally require no pruning other than to remove dead or broken branches. These should be removed 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.

Propagation

Monkey puzzle tree is tough to propagate by vegetative means, so it is normally done by collecting and planting seeds.

Pests and Diseases

Common Pests & Plant Diseases

Monkey puzzle tree is generally resistant to pests and diseases, but there can be occasional problems with scales, mealybugs, thrips, and spider mites. Neem oil or another horticultural oil are good remedies.

Leaf spot, sooty mold, and phytophthora root rot are rare but possible disease issues.2 Mold and leaf spots 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 

Homeowners sometimes come to lament the messiness of monkey puzzle trees, which can drop large quantities of big, hard cones in the fall once the tree is mature, often assaulting pedestrians walking below. Trees with substantial surface roots may also heave sidewalks, driveways, and patios. This tree gets surprisingly large, so plant it 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 ages; however, it’s a natural process.

Potting and Repotting 

Like its relative, Norfolk pine, monkey puzzle tree is sometimes grown as a container plant in regions where it cannot survive winters outdoors. It is best to give it plenty of outdoor time during the summer in cooler climates, 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 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 in any well-draining potting mix in any type of pot with good drainage. When roots begin poking out of the drainage hole every few years, 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.

Overwintering

Monkey puzzle tree requires no protection against the winter cold when grown in-ground in its established hardiness range. Gardeners growing it as a container plant in cold-winter regions should move it indoors as temperatures begin to dip below freezing. A potted tree will need as much light as you can give it during the winter months.

III. Uses and Benefits 

The monkey puzzle tree is grown for its unique architectural appearance. Other qualities that attract gardeners are its slow, manageable growth and its adaptability to various soil types. Most often it is used as a focal point or specimen tree on a patio or lawn. It looks striking grown in a small grove and does well in coastal gardens.

Monkey Puzzle (Araucaria araucana) Details

Common name Chilean Pine, Chile Nut, Chile Pine, Monkey Puzzle, Monkey Puzzle Tree, Monkeypuzzle Tree, Monkey Tail Tree, Parana Pine, Pehuen, Pewen, Pinonero
Botanical name Araucaria araucana
Plant type Edible
Hardiness zone 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b
Growth rate Medium
Harvest time Fall
Height 50 ft. 0 in. - 80 ft. 0 in.
Width 50 ft. 0 in. - 80 ft. 0 in.
Sunlight Full sun (6 or more hours of direct sunlight a day)
Soil condition Clay
Leaf color Green