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Characteristics of Manuka Tree (Leptospermum scoparium) in the Wild

Published by: Admin on March 16, 2024
Categorized in: Flower Tree

Manuka or Tea Tree (Leptospermum scoparium) is a species of plant in the Myrtaceae family, which originated in Australia before the Miocene drought, eventually spreading from eastern Australia to New Zealand.

HISTORY

Evidence suggests that Leptospermum scoparium originated in Australia before the onset of the Miocene drought, and spread as a result of a long-distance dispersal event to New Zealand from eastern Australia sometime in the last 20 million years. Typhoons and other wind activity are likely responsible for transporting seeds over long distances. Supporters of this claim cite evidence that the genus Leptospermum arose in conditions where forest fires were frequent (namely in Australia, and not in temperate New Zealand) because they have fire-adaptive traits such as serotiny and storage lignotubers.

Today manuka trees can be found throughout almost all of New Zealand, but their concentration is on the drier east coast of the North Island and South Island. Meanwhile, in Australia, they are in Tasmania, Victoria and New South Wales.

The name “Manuka” itself comes from the Māori language which is also used to refer to “Jelly Bush” and “Tea Tree” in Australia and also in New Zealand. This name appeared because Captain Cook used the leaves to make “Tea” drinks.

CONFUSION

Manuka (Leptospermum scoparium) is often confused with the related species Kanuka (Kunzea ericoides). The easiest way to tell the two species apart is by feeling the leaves. Manuka leaves are prickly, while kanuka leaves are soft. Alternatively, manuka seed capsules are larger (5-7 mm diameter) and often remain on the tree throughout the year, whereas kanuka seed capsules are much smaller (2-4.5 mm diameter), and do not appear for most of the year.

Characteristics of Manuka Leaf

Leptospermum scoparium Leaf — Source: Morgan Fox

Leaves are alternate with circular, almost sessile, stiff, leathery, pointed, erect or horizontally projecting, margins intact, aromatic leaves are lanceolate, elliptical or ovate, lanceolate to oval, ovate, 4-12 mm long and 4- 6mm. They have transparent oil glands.

Characteristics of Manuka Flower

Leptospermum scoparium Flower — Source: Sam Ayre

The flowers are white, sometimes pink, 8-15 mm in diameter (rarely up to 25 mm), with five petals.

Characteristics of Manuka Fruit

Leptospermum scoparium Fruit — Source: Seth Mckenzie

The fruit is multi-seeded with five chambers, woody, glabrous, hemispherical, and reddish brown in color. In size, it stands out prominently above the flower cup. The fruit remains in place for a year or more. The seeds are smooth, elongated and reddish brown with a length of 2-3 mm.

Characteristics of Manuka Tree

Leptospermum scoparium Tree — Source: Michael Berardozzi

Manuka grows as a productive shrub or small tree and is often one of the first species to regenerate in cleared land. It usually grows to a height of 2-5 meters but can grow into a medium-sized tree, up to 8 meters or more. The wood is hard and durable.

Many cultivars of Leptospermum scoparium have been developed as ornamental garden trees, potted plants, or bonsai subjects, the following have gained the Royal Horticultural Society’s Award of Garden Merit (AGM):

Leptospermum scoparium ‘Kiwi’
Leptospermum scoparium ‘Nichollsii Nanum’
Leptospermum scoparium ‘Red Damask’
Leptospermum scoparium ‘Silver Sheen’

There are many more cultivars available in New Zealand but often the trees perform better when cultivated overseas. This is because in its homeland this plant is easily attacked by insects that secrete honeydew on which sooty mold grows which ultimately weakens the tree. Therefore, attempts have been made, with limited commercial success, to cross showy New Zealand cultivars with mildew-resistant Australian Leptospermum species.

Benefits of Manuka

The wood is often used for tool handles. Manuka sawdust provides a delicious flavor when used to smoke meat and fish. The wood is also used for carvings.

The tree is cultivated in Australia and New Zealand for manuka honey, produced when honey bees collect nectar from its flowers, and for the pharmaceutical industry.

The essential oil, which many claim is medicinal, is produced by steam distilling the leaves.

A decoction of the leaves is drunk to treat urinary complaints and as a medicine to reduce fever. The steam of leaves boiled in water is inhaled to treat colds.

A decoction made from the leaves and bark produces a warm liquid that can be applied to stiff muscles and sore joints.

An emollient white gum, called manuka pie, is given to nursing babies and is also used to treat burns.

Chewing the bark is said to have a relaxing effect and improve sleep quality.