Araucaria - Monkey Puzzle Tree: Planting and Care

Botany and Description

The botanical genus Araucaria belongs to the Araucariaceae family and takes its name from the Araucanía region in Chile, where two species of the genus are native: the Chilean Araucaria and the Araucaria angustifolia. Araucarias were already present during the Mesozoic era, as evidenced by fossils discovered in various regions of the world, including India, Africa, America, and Australia.

Regarding their current geographical distribution, it is much more limited and primarily confined to specific regions. For example, a large proportion of the genus’s species are endemic to New Caledonia, with 16 out of the 20 species recorded worldwide, where they have adapted to various altitudes and soil types. These trees are found in coastal areas, low and mid-altitude zones, and some peaks above 1,000 metres.

Araucaria rulei, botanical plate, circa 1870

Regarding the different species, the Chilean Araucaria or “Monkey Puzzle” (Araucaria araucana) is the most commonly cultivated in Europe and the hardiest in temperate climates. The Norfolk Island Pine (Araucaria heterophylla) and the Columnar Araucaria (Araucaria columnaris) are also frequently planted in warm coastal regions and temperate areas with very mild winters.

Araucarias are gregarious species that never form dense forest stands. They prefer steep, sunny slopes and are often planted as ornamental trees in large gardens or parks. Several species are also cultivated for their timber or for aesthetic reasons.

The trunk of these conifers is typically very straight and may be covered with a resinous bark, rough and thick. This bark can vary in colour, ranging from greyish to reddish, and can account for up to 25% of the trunk’s volume. It often features a polygonal tile-like pattern corresponding to the scars of former branch insertions.

The stems or branches are arranged in a spiral and can be horizontal or slightly concave. When the tree is young, the lower branches often touch the ground, giving the tree a pyramidal shape. As it ages, the lower branches fall away, the trunk becomes exposed, and the crown tends to become more open, taking on an umbrella-like shape.

The “leaves” of Araucarias are very distinctive. They are either needle-like or triangular scales, dense and overlapping, forming a cylindrical sheath around the branches. These leaves are leathery, evergreen, and have a long lifespan, lasting from 10 to 15 years.

Different types of “foliage”: on the left, that of Araucaria araucana, top right that of A. excelsa, and bottom right that of A. heterophylla.

Regarding flowers and cones, Araucarias are generally dioecious, meaning that male and female cones are usually found on separate trees. However, it can happen that Araucarias practice monoecy by producing male and female cones on the same individual. Male cones are elongated and found at the ends of branches. They are yellowish-brown at maturity and bear several pollen sacs. Female cones are more globular and can reach the size of a melon. They consist of around 700 scales and take approximately 18 months to 3 years to mature. Once mature, they disintegrate to release the winged seeds, which are often edible.

Female cone of Araucaria columnaris

It is worth noting that Araucaria is also adapted to withstand fires, thanks to its thick bark, the protection of its buds, and its ability to produce buds directly on the trunk (epicormic buds). It is therefore found in areas regularly affected by human-induced fires or near active volcanoes.

The main species of Araucaria

Araucaria araucana - Monkey Puzzle

The Monkey Puzzle Tree is a large conifer that is both unique and strikingly graphic. Its branches, arranged in a geometric pattern, are covered with very hard, sharp, scale-like leaves of a glossy green. Best suited for large gardens!

• Height at maturity 15 m

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Planting the Araucaria

Where to Plant?

These trees prefer a sunny location but can also tolerate partial shade. Ensure the tree receives at least a few hours of direct sunlight each day to encourage vigorous growth.

The type of soil is also crucial for the health of the Araucaria, as they prefer well-drained soil rich in organic matter. Avoid clay or overly wet soils, as they can lead to drainage issues and affect the tree’s growth.

Additionally, these trees are best suited to temperate to subtropical climates and may not withstand extremely cold temperatures well. The Araucaria is hardy only down to -12°C.

Nota bene: The Araucaria is a tree that can grow to a considerable size, so it is important to consider spacing when planting. Ensure you leave enough space between the Araucaria and other plants (especially large trees) or nearby structures: allow for around 15 metres.

Araucaria araucana: a tree suited to large gardens or parks.

When to Plant?

Spring is often considered the ideal time to plant an Araucaria. The milder temperatures and longer days provide optimal conditions for the tree to establish itself. This also gives the Araucaria enough time to acclimatise before winter arrives.

However, autumn is another favourable time for planting Araucaria. Cooler temperatures and more regular rainfall help reduce water stress, allowing the tree to establish more easily.

How to Plant?

The first step is to prepare the soil. The Araucaria prefers well-drained soil rich in organic matter. Before planting, it is advisable to work the soil by incorporating compost or organic matter.

• Soak the pot of your Araucaria in a bucket of water for a few minutes to thoroughly rehydrate the root ball
• Dig a hole twice as deep and wide as the root ball and loosen the soil at the bottom of the hole
• Throw a few handfuls of well-rotted compost into the bottom of the hole
• If your soil is heavy, you can add some sand or even gravel to improve drainage
• Place the root ball in the hole, spreading the roots out if possible
• Fill the hole with the excavated soil, previously loosened
• Gently firm the soil around the tree with your hands (not your feet!)
• Water the base with 10 litres of water to reduce the risk of “air pockets” between the roots and the soil
• Apply mulch to protect the young tree from drought or plant some ground cover plants directly at the base (Bugle, Sweet Woodruff, Glechoma, Geranium macrorrhizum…).

Note: staking an Araucaria at planting can be useful in certain circumstances, particularly if the tree is planted in an area exposed to strong winds. Staking helps stabilise the tree while it establishes its root system, which is especially important during the first few months after planting. If you’d like to learn more, read Should Trees Always Be Staked?

Size and Maintenance

Pruning

The Araucaria requires little pruning. In fact, excessive pruning can even be harmful. If you need to prune your Araucaria, do so with caution. Remove only dead or damaged branches and avoid cutting the main branches, as this can unbalance the tree and affect its future growth.

Maintenance

The maintenance of the Araucaria is quite limited. These trees prefer well-drained soil and appreciate regular watering, especially during dry periods. An organic mulch around the base of the tree can help retain moisture and provide essential nutrients.

Fertilisation

Fertilisation is generally not necessary for the Araucaria, especially if the tree is planted in soil rich in organic matter. However, a balanced fertiliser can be applied in spring to encourage vigorous growth.

Diseases and potential pests

Araucarias can be susceptible to certain types of fungal diseases and pests, although this is relatively rare.

Symptoms such as yellowing needles or spots on the leaves may indicate a fungal infection, such as rust caused by a fungus called Mikronegeria fagi. In such cases, a natural fungicide treatment may be necessary to control the disease.

Pests such as aphids and scale insects can also cause problems. These small insects feed on the tree’s sap, weakening the Araucaria and making it more susceptible to diseases.

Propagation

• Propagation of Araucaria by Seeds

The most common method for propagating Araucaria is by seeds. The seeds are harvested from female cones which naturally disintegrate to release the winged seeds. Once the seeds are harvested, they should be sown in a well-draining substrate (moist sand or very light potting mix) and kept at a constant temperature of around 20 to 25 °C. Germination can take several weeks, or even months. It is crucial to keep the substrate moist but not waterlogged to encourage germination.

Araucaria seeds on female cones

• Propagation of Araucaria by Cuttings

Propagation by cuttings is less common but still possible. This method involves taking a cutting of about 15 to 20 cm in length from a healthy tree. The cutting is then planted in a mixture of potting soil and sand and kept at a constant temperature. Rooting can take several months, and the results are variable.

Pairing the Monkey Puzzle Tree

Creating a harmonious and beautiful scene around an Araucaria requires careful consideration of the colours, textures, and heights of the surrounding plants. The Araucaria, with its needle-like or scale-like leaves and its majestic stature, is already a centrepiece in any garden. It is therefore wise to pair it with plants that complement rather than compete with its appearance.

At the base and around the Araucaria, consider evergreen perennials such as certain ferns (for example, Polystichum neolobatum), which add a soft texture and deep green that contrasts well with the Araucaria’s more rigid foliage. Hostas can also be a great option, as they offer a wide variety of leaf colours and textures.

Araucaria araucana and Polystichum neolobatum (© Wendy Cutler)

To add colour, consider flowering plants that bloom in different seasons. Azaleas and rhododendrons are excellent choices for spring, while hydrangeas can bring a splash of colour in summer. Cyclamens, on the other hand, are perfect for adding interest in autumn and winter.

If you wish to add other trees or shrubs, opt for those with a different shape or foliage texture to create an interesting contrast. For example, a Himalayan birch with white bark can be an excellent addition, as can a Japanese maple with delicate leaves.

The majestic Araucaria araucana, surrounded by a Japanese maple and a Himalayan birch (© Leonora Enking)

To cover the ground, groundcovers such as ivy or periwinkle can be used to fill empty spaces and add a touch of greenery. They are also useful for controlling weeds.

Anecdotes

• The name “Monkey Puzzle” is often attributed to the Araucaria araucana. This name comes from the unique arrangement of its branches and spiny leaves, which would make the tree difficult to climb, even for a monkey. However, no large primates inhabit the natural range of this tree. Therefore, it is unknown whether it is truly difficult for a monkey to climb…
• Some specimens of Araucaria araucana have been estimated to be over 1,000 years old, making them living witnesses to history.
• In New Caledonia, where several species of Araucaria are endemic, these trees hold great cultural significance. They are often associated with local legends and are considered symbols of strength and longevity.
• The Chilean Araucaria became the national tree of Chile in 1990.
• The seeds of certain Araucaria species are edible and even serve as a food source for local populations in some regions. They are often compared to pine nuts in terms of taste and texture. However, when in doubt, do not consume the seeds of your Araucaria!!