How to Grow and Care For Monkey Puzzle Trees

Monkey puzzle tree (Araucaria araucana) is an evergreen conifer tree that grows in mountainous regions of South America. It can grow in some parts of the U.S. in zones 7 through 10, although it can't tolerate freezing temperatures. It is a long-living species (it can live over 1,000 years) that still exists and has been present on Earth since the dinosaurs and is sometimes called a living fossil; however, it is now threatened by climate change.

Monkey puzzle tree looks much different than most conifers featuring unique-looking spikey protrusions. 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 long-lived tree, taking 10 years to reach 20 feet in height. It has been known to reach 80 feet in height in the wild, but garden trees usually reach a maximum of 20 to 30 feet.

Monkey Puzzle Tree Care

Monkey puzzle tree is easy to grow in the right climate—but temperamental in many locations. Mediterranean-type environments at high elevations are ideal, but northern regions or areas with hot summers will require just the right site. Not every place within the zones 7 to 10 hardiness range will be suitable—only regions with relatively cool summers and mild winters and areas without severe urban pollution issues. Although forgiving of different soil types, the monkey puzzle tree requires a sheltered area protected from winds. In areas with hot summers, some afternoon shade is preferred.

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 environment includes coastal regions, the tree has developed excellent salt tolerance.  

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 depth as it was growing in the container. It is always good to have a helping hand to ensure 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 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 during the first year 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.  

Light

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. 

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. 

Water

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.  

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 be moved back and forth between outdoor and indoor locations as the seasons shift.

Fertilizer

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.

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.

Propagating Monkey Puzzle Tree

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

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. 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.

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. 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.

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 rare but possible disease issues. 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 With Monkey Puzzle Tree

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 can also heave sidewalks, driveways, and patios. This tree can get 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.