Rimu Tree Guides & Information

Dacrydium cupressinum General Information

There is a wealth of information about Dacrydium cupressinum and The Plant Company is often asked specific questions which we have laid out here!

Dacrydium cupressinum Information

Dacrydium cupressinum, commonly known as Rimu, is a large evergreen coniferous tree endemic to New Zealand. It has red wood and reaches a height of 35–60 m (115–197 ft), with a trunk 1.5–2 metres (4.9–6.6 ft) in diameter. The bark is flaky and dark-brown in coluor. In its juvenile stages the branches are thin and numerous, but as the tree grows older around three quarters of the tree becomes branchless. It has a lifespan of 600–800 years, but may reach beyond 1000 in rare cases. The yellowish-green foliage varies in size and shape between the juvenile, sub-adult, and adult life stages.

Rimu is usually found in lowland and montane forest, but also occurs in subalpine scrub on Stewart Island. It is a true rainforest tree and in some forests is the predominant canopy tree, while in others it is more scattered and may be seen only as an emergent tree. Rimu usually occurs in mixed forests in association with other Podocarps, Hinau or Pokaka, Tawa and Beech.

What Are The Common Names For Dacrydium cupressinum?

Dacrydium cupressinum has several common names, but some are more widely used than others. The most popular common name is Rimu and this is both widely used and recognised. Some less common names include:

• Red Pine - This name is not as commonly used nowadays and can be misleading as Rimu isn't a true pine tree.
• Huarangi - This is a Maori name for Rimu, but its more common meaning in Te Reo Maori is "to be drunk, intoxicated, mad, or deluded" or "dew".
• Southern Conifer, Puaka - These names are rarely used and not widely recognized.

Rimu Tree General Information

There is a wealth of information about Rimu trees and The Plant Company is often asked specific questions which we have laid out here!

Are There Male And Female Rimu Trees?

Rimu trees are dioecious, meaning that they have separate male and female trees. The male trees produce pollen cones, while the female trees produce seed cones. The pollen from the male trees is carried by the wind to the seed cones on the female trees, where it fertilises the seeds. The seeds then develop into fruit, which are eaten by birds and other animals. The birds and other animals then disperse the seeds, helping to spread Rimu populations.

Most plants sold are grown from seed, so it is near impossible to determine if they are male or female until they flower at about 20 years of age.

Can You Eat Rimu Fruit?

Fruit from a Rimu tree is a small and fleshy fruit that is red when ripe, and can be eaten. The fruit has a sweet and tart taste and is often eaten by birds. It is a good source of vitamin C and antioxidants. However, it is important to note that Rimu fruit can also be toxic in high doses. It can cause nausea, vomiting, and diarrhoea.

If you are considering eating Rimu fruit, it is important to identify the fruit correctly. Rimu fruit can be easily confused with other fruits, such as Miro and Tanekaha, which are poisonous. If you are unsure whether or not a fruit is Rimu, it is best to err on the side of caution and not eat it.

How Long Do Rimu Trees Live?

Rimu trees are long-lived trees, with some specimens estimated to be over 1,000 years old. The average lifespan of a rimu tree is around 500-600 years, but they can live for much longer.

How Long Does It Take For Juvenile Rimu Tree To Mature?

There's no single definitive answer to how long it takes a juvenile Rimu tree to mature, but it's a slow process that can take decades:

• The most noticeable sign of a maturing Rimu is a shift in its crown shape. Juvenile Rimu trees have a bushy, open structure with drooping branches. As the tree matures (around 20 years old), the crown begins to transform into a distinctive conical shape.
• Estimates suggest it can take around 20 years for a juvenile Rimu to reach this stage of crown maturity. However, this is just an approximation, and the actual time can vary depending on:
  • Growing Conditions: Factors like sunlight, soil quality, and moisture levels can influence growth rate. Ideal conditions will promote faster growth.
  • Genetics: Some individual Rimu trees may have a naturally faster or slower growth rate due to genetic variations.
  • Competition: Competition for resources from other plants can slow down a Rimu's growth.

Is Rimu A Maori Tree?

Rimu is considered a Maori tree in two ways:

• Rimu is endemic to New Zealand, meaning it grows naturally nowhere else in the world. Māori are the indigenous people of New Zealand, and the land and its plants have been central to their culture for centuries.
• The Rimu tree holds cultural significance for Maori. The wood was traditionally used for tools, carvings, and even medicine. The bark was used for fires, and the grubs found near the roots of trees associated with Rimu were used as pigment for moko (facial tattoos).

Is Rimu Native To NZ?

Rimu (Dacrydium cupressinum) is native to New Zealand. In fact, it's endemic, meaning it grows naturally nowhere else in the world. This makes Rimu a truly special tree and a significant part of New Zealand's unique ecology and cultural heritage.

What Are Some Facts About The Rimu Tree?

Rimu trees boast a collection of fascinating facts that highlight their ecological importance, cultural significance, and unique characteristics:

• Rimu are ecological giants, reaching towering heights of up to 60 m (197 ft) and boasting lifespans that stretch for centuries. Some Rimu trees have even been documented to be over 1,000 years old.
• Rimu trees play a vital role in the New Zealand ecosystem. Their fruiting cycle is a bit of a mystery, with trees only producing a bounty of small, fleshy fruits every few years. This feast is perfectly timed for another New Zealand icon, the endangered Kakapo parrot. The Kakapo relies heavily on these fruits for food, highlighting the interconnectedness of the ecosystem.
• Rimu wood is known for its reddish-brown hue and fine grain, making it a prized resource for Maori and early European settlers. Traditionally, Maori used Rimu for carving tools, waka (canoes), and even buildings. Later, European settlers prized Rimu for furniture and building materials. Today, due to its slow growth rate and cultural significance, Rimu logging is strictly controlled.
• Rimu leaves were used by Maori for various purposes, particularly related to skin health. There are accounts of Rimu leaves being applied to treat skin sores, although the details and safety of this traditional practice are not scientifically established. Interestingly, Captain Cook even used the bark and leaves of Rimu to make a spruce beer for his crew to prevent scurvy!
• Rimu trees have a unique relationship with a tiny insect called the scale insect. These insects feed on the sap of the Rimu, but in return, they also produce a sugary substance called honeydew. This honeydew attracts other insects, including beneficial ladybugs that help control pest populations on the Rimu tree. It's a fascinating example of symbiosis in action.

What Are The Characteristics Of Rimu?

Rimu trees have a unique set of characteristics that make them a fascinating and iconic tree for New Zealand. Some of these key features include:

• Rimu can reach impressive heights of 35-60 m (115-197 ft), making them giants of the forest.
• The trunk can reach a width of 1.5-2 m (4.9-6.6 ft).
• These trees are incredibly long-lived, with lifespans of 600-800 years being common. Remarkably, some specimens can even exceed 1000 years.
• Rimu's crown undergoes a transformation throughout its life. Young trees have a bushy, open structure, while mature trees develop a distinctive conical shape.
• The bark is a fascinating indicator of age. Young trees have smoother bark, but as they mature, it becomes a signature flaky, reddish-brown colour. This bark sheds in large flakes, leaving a wavy patterned texture on the trunk.
• Rimu is an evergreen tree with unique foliage that changes with age. The leaves are small and scale-like, with a yellow-green hue. Juvenile trees sport longer, pointed leaves, while mature trees have shorter, flatter ones.
• The branching pattern of Rimu is another interesting feature. Young trees boast numerous, slender branches that droop gracefully. As the tree matures, the lower branches die off, and the remaining ones become long and drooping as well. The top portion of a mature tree has a thinner canopy with fewer branches.
• Rimu thrives in lowland and montane forests of New Zealand, occasionally venturing into subalpine scrub.
• Rimu trees are dioecious, meaning there are separate male and female trees. Female trees produce small, bright red, fleshy fruits that attract birds for seed dispersal.
• Rimu holds a special place in Maori culture, traditionally used for tools, carvings, medicine, and even pigments for facial tattoos.

By understanding these characteristics, you can gain a deeper appreciation for the Rimu tree, a majestic symbol of New Zealand's natural heritage.

What Are The Rimu Leaves Used For?

Traditionally, Rimu leaves were used by Maori for various purposes, particularly related to skin health. In particular, there are accounts of Rimu leaves being applied to treat skin sores but details of the preparation and use are not widely documented.

What Did Maori Use Rimu For?

Maori used Rimu for a wide range of purposes, making it a valuable resource in their culture:

• Rimu's strong, reddish-brown wood was perfect for crafting tools and weapons. Maori fashioned war spears, patu (clubs), and toki (adzes) from Rimu for hunting, fighting, and woodworking. They also used Rimu timber for building waka (canoes), essential for transportation and navigation.
• Rimu wasn't just for practical applications; it played a role in Maori medicine. There are accounts of using Rimu leaves for treating skin sores. The bark was used for fires, as it produces little smoke and has a distinct smell. Interestingly, the heartwood of Rimu, along with a special grub found near Rata trees, was used to create a black pigment for moko (facial tattoos).

What Do Rimu Leaves Look Like?

Rimu leaves are quite distinctive and change in appearance as the tree matures:

• Juvenile Leaves: On young Rimu trees, the yellow-green leaves are longer and more prominent. They can be 0.4 to 10 mm long and 0.5 to 0.1 mm wide. These juvenile leaves often have a sharp point at the tip.
• Mature Leaves: As the Rimu tree matures, the leaves become smaller and flatter. Mature Rimu leaves are typically only 3-4 mm long and 1 mm wide, with a less pointed tip and a more triangular shape.
• Texture: Rimu leaves feel soft and pliable on young trees, but become more rigid and prickly to the touch as the tree matures.

What Does A Juvenile Rimu Tree Look Like?

A juvenile Rimu tree has a distinct appearance that sets it apart from its mature counterpart:

• Shape: Young Rimu has a bushy, open structure. Imagine a pyramid shape with softer edges, created by numerous branches growing outwards.
• Branching: The branches of a juvenile Rimu are thin and slender. They tend to droop gracefully, creating a cascading effect, especially when the tree is young.
• Foliage: The leaves on a juvenile Rimu are more prominent than those on a mature tree. They are yellow-green in colour and have a feathery appearance.
• Bark: The bark of a young Rimu is smoother compared to the mature tree's rough and flaky exterior. It may have a slightly reddish tint.

What Does A Rimu Tree Look Like?

There are several key features you can look for to identify a Rimu tree:

• Rimu can grow quite tall, reaching heights of 35-50 m (115-165 ft) with a straight trunk. Mature trees have a distinctive conical crown shape.
• The bark of a Rimu is a good indicator of its age. Young trees will have smoother bark, but as they mature, the bark becomes flaky and a dark reddish-brown colour. This bark sheds in large flakes, leaving a wavy patterned texture on the trunk.
• Rimu is an evergreen tree with small, scale-like leaves. These leaves are yellow-green and vary in size depending on the age of the tree. Juvenile trees will have longer, more pointed leaves, while mature trees have shorter, flatter ones.
• Rimu trees go through distinct stages in their branching pattern. Young trees have numerous, slender branches that droop. As the tree matures, the lower branches die off and the remaining branches become long and drooping as well. The upper portion of the mature tree has a thinner canopy with fewer branches.
• Rimu trees are commonly found in lowland and montane forests.
• Rimu trees are either male or female. Female trees produce small, round fruits that are bright red and fleshy.

What Is Huarangi?

Hurangi is the maori name for fruit from the rimu tree.

Where Can You Find Rimu Trees?

Rimu trees are native to New Zealand, and can be found throughout the country, from the North Island to the South Island to Stewart Island/Rakiura. They are most common in lowland and montane forests, and can also be found in high-altitude forests.

Some of the best places to see Rimu trees in New Zealand include:

• Kauri Coast: The Kauri Coast is a region in the North Island that is home to some of the largest and oldest Rimu trees in the country.
• Waipoua Forest: Waipoua Forest in the North Island is home to Tane Mahuta, the largest known Rimu tree in New Zealand.

Planting And Growing Rimu Trees

Planting a Rimu and getting it to grow well is generally easy when you get a few of the basics right. This involves planting them in the right soil type, choosing the most ideal planting position, and ensuring the plants have the essentials to thrive. The Plant Company has the right advice to ensure success!

How Do You Plant A Rimu Tree?

Choose a full sun position or partial shade position with good drainage for your Rimu tree. The hole should be dug to at least 50-75% deeper and wider than the container the plant is currently growing in. A planting spade makes the hole digging a lot easier. The Plant Company recommends incorporating compost or sheep pellets into the soil to provide additional organic material, but this is not essential. Do not put fertiliser in the bottom of the hole, rather spread that on the soil surface after planting, and preferably do this when the plant is actively growing in spring.

Remove the plant from the container it is growing in by either pulling it free or by cutting the bag. We recommend cutting the bag, especially for larger grade plants, to minimise any chance of damaging the roots. If the roots are bound up, you can tease them apart if you want but this is not essential. The Plant Company does not advise cutting through roots, even if the plant is rootbound, as that injures the plant.

Now place the plant in the hole and make sure it is level with the soil surface before filling in around it. If it is above the soil surface, dig more out. If it is below, put in more soil and retest the level. Once the plant is set level with the soil surface, add more soil gradually and firm it around the plant using gentle pressure as you go. Scatter Native Plant Fertiliser across the soil surface after planting and then give the plant a good watering. Finally, you may want to consider staking it to provide additional protection from wind.

How Fast Do Rimu Trees Grow?

Rimu trees are slow-growing trees, typically grow 10-20 cm per year in height. However, Rimu trees can live for many years, and some specimens have been known to reach heights of over 50 metres.

Where Can I Grow A Rimu Tree In New Zealand?

Rimu trees are relatively adaptable but thrive in specific conditions. If you are considering to plant one, here are a few things to consider:

• Climate: Rimu prefers cool, moist environments and tolerates some frost. They wouldn't do well in dry, hot areas.
• Soil: Well-drained, slightly acidic soil with good organic matter content is ideal. Clayey or poorly draining soils can lead to root rot or tree death.
• Light: Rimu can tolerate full or partial shade.
• If you're unsure about the suitability of your specific location, consulting with a local nursery.

Remember, Rimu are slow-growing and may take many years to reach maturity. But with proper care and patience, you can grow a magnificent Rimu tree.

Where Do Rimu Grow Best?

Rimu grow best in a variety of conditions, but specific factors contribute to their optimal growth: - They prefer mild temperatures with cool winters and warm, humid summers. - High rainfall is vital, typically needing at least 1000 mm per year and ideally more in dryer areas. - Well-drained fertile soil is ideal, as they can tolerate some moisture but not prolonged waterlogging. They can grow in poorly drained soils, but growth rates and tree form are generally not great. - While preferring full sun, they can tolerate partial shade. Deep shade can stunt their growth. - Wind protection is beneficial, especially for young trees. Strong winds can topple mature Rimu due to their size and shallow root systems. - Rimu are generally found at lower altitudes, ideally below 600 meters, but they can survive higher up in sheltered areas.