The Monkey Puzzle Tree (Araucaria araucana) is a distinctive, ancient evergreen conifer. Often called a “living fossil,” its lineage dates back over 200 million years. Native to the volcanic slopes of the Andes Mountains in Chile and Argentina, the tree is known for its slow growth rate and striking, symmetrical branches covered in thick, sharp, scale-like leaves. Its unusual, umbrella-shaped crown develops as it matures, making it a long-lived addition to the garden.
Ideal Placement and Soil Preparation
Selecting the permanent site for a Monkey Puzzle Tree requires foresight, as this long-lived species should not be moved once established. The tree requires ample space to accommodate its mature size, reaching up to 60–70 feet tall and 30–35 feet wide in cultivation. Therefore, it must be sited well away from buildings and utility lines. It thrives best in an open location that receives full sun, though it can tolerate partial shade, especially in climates with intensely hot summers where afternoon shade is beneficial.
Replicating the tree’s native habitat—well-drained volcanic soil—is paramount for successful establishment. Excellent drainage is a strict requirement, as the tree is highly susceptible to root rot in waterlogged or heavy clay soils. If the existing soil is heavy, amend it with grit or sand, or plant the tree on a slight mound to ensure water moves away quickly.
When planting, dig the hole twice as wide as the root ball but only as deep as the root ball itself. Position the tree so the top of the root ball is level with the surrounding soil to prevent planting too deeply, which can lead to root suffocation. While the tree is not overly particular about soil pH, it prefers slightly acidic conditions, ideally between 5.5 and 6.5.
Essential Watering and Nutrient Needs
Watering requirements for the Monkey Puzzle Tree change as it transitions from young to established. Young trees require consistent moisture during their first two to three growing seasons to establish a robust root system. During this establishment phase, the soil should be kept evenly moist but never waterlogged.
Once mature, the tree becomes much more drought-tolerant, but it still benefits from deep watering during prolonged dry spells. Applying a two to four-inch layer of organic mulch around the base helps regulate soil temperature and retain moisture. However, the mulch must be kept away from the trunk to prevent moisture buildup and potential rot.
The Monkey Puzzle Tree is generally a low-maintenance species with minimal nutrient demands. Fertilization is not routinely necessary and should only be considered if the tree exhibits signs of nutrient deficiency or is growing in poor soil. If fertilization is necessary, a balanced, slow-release fertilizer can be applied once in the spring to support healthy growth. Pruning is rarely needed, as the tree naturally develops its distinctive shape; maintenance involves cleanly removing any dead or damaged lower branches at the trunk.
Protecting the Tree from Pests and Cold
While the Monkey Puzzle Tree is relatively resistant to pests, occasional issues arise, particularly when the tree is under stress from poor growing conditions. Common biological threats include scale insects, mealybugs, and spider mites, which can often be managed by applying horticultural oil to the affected areas. Fungal diseases like leaf spot and root rot are also possible, with root rot being the most common problem resulting from poorly draining soil.
The tree is hardy in USDA zones 7 through 10 and can tolerate brief temperature dips below freezing. Younger trees are more vulnerable and benefit from winter protection in the colder reaches of this range. Protection involves insulating the root zone by applying a thick layer of mulch and shielding the foliage from harsh, drying winter winds, which can cause desiccation.
For smaller trees, temporary windbreaks, such as burlap screens or fences, can be installed to block the prevailing wind direction. Unlike some other evergreens, the Monkey Puzzle Tree does not tolerate air pollution well, and its growth can be negatively impacted in heavily urbanized areas. Ensuring a sheltered location that minimizes exposure to strong winds is crucial for long-term tree health.