The kanuka tree is one that is found specifically in New Zealand. Kanuka isn’t as well as known outside its native land as the similar-sounding manuka tree and you might be surprised to know that kanuka honey exists, too.
The kanuka tree is very common in New Zealand and is often confused with the manuka tree in more ways than just the name, as we’ll see below.
Let’s take a look at 7 questions about the kanuka tree and answer each in detail.
Where do kanuka trees grow?
Research has shown that kanuka trees are endemic to New Zealand so they are only found there. Kanukas tend to grow throughout the lowlands of the North Island and in the South Island as far down as Dunedin. They can survive droughts due to their woody roots and once established, can withstand other harsh conditions.
Kanukas tend to grow well in most soil types except water-logged environs although they are very tolerant to varying weather conditions including wind, drought and frost. Having said that, kanukas prefer a warmer temperature than manukas and tend to grow faster as a result.
Kanuka is part of the myrtle family and is an evergreen that grows year round. You may also hear it referred to as white tea tree or white manuka.
Like the manuka, kanukas are often considered to be invasive shrubs depending on the location and are often treated as weeds if they disrupt other vegetation.
How high do kanuka trees grow?
Kanuka trees grow to between 33′ – 82′ (10m – 25m) in height and generally live to be about 150 years old which means they tend to live longer than manuka trees do.
An average manuka tree will grow to about 15m in height and have a diameter of 6″ – 16″ (15 cm – 40 cm).
Kanukas are often contorted in shape due to heavy winds and are capable of growing in the absence of soil including in between rocks and crevices.
What kills kanukas trees?
While kanukas are considered a shrub or small tree, they do often get outgrown by other larger tree species. One of the things they don’t generally have to worry about however is animals – if we ignore the human kind for a second – as wildlife doesn’t consume the tree as food.
Part of the reason kanukas die is that they act as shade for smaller saplings of other tree types. When those young trees grow larger, they often tower over kanukas and shield them from the sun, killing some of them off.
Kanukas can also be killed by severe frosts when they are young and they won’t survive in extremely wet soil that isn’t drained well.
Myrtle rust disease is a fungus which attacks kanukas, manukas and other myrtle trees and can kill them. New Zealand and Australia have both seen outbreaks that have caused significant damage to these and other trees including pohutukawas.
And of course kanukas can be killed by humans, particularly farmers or others who view the tree as a nuisance in the course of their business and either fell the trees or burn them to clear the brush.
What’s the difference between kanuka and manuka trees?
Kanuka and manuka trees are often mistaken for one another given their similarities in look and name and their prevalence in New Zealand. There are several ways to tell the difference however.
Other than kanukas tending to grow taller than manukas, there are a few other distinguishing characteristics:
- Kanukas have smaller flowers that tend to grow in clumps whereas manuka flowers are singular, larger and spread over the bush.
- Kanukas tend to flower from November to February whereas manukas flower earlier from October to January.
- Kanukas have light brown colored bark that is in thin strips and leathery in feel whereas manuka bark is flaky, has wider strips and tends to have a reddish hue to it.
- Kanuka leaves are narrow and softer to the touch than manuka leaves which are also more broad and pointed.
- While neither kanukas or manuka trees get eaten by animals, geckos can consume the kanuka flowers and the nectar.
- Unlike manuka, kanuka trees have no MGO (methylglyoxal) present in high concentrations which is a chemical that is believed to provide many of the antibacterial properties contained in manuka honey.
Is kanuka a hardwood?
Kanuka is a hardwood that tends to burn long and slow when used in fires which is a long established use for the wood. It is considered a hard and strong timber. Like manuka, kanuka is generally referred to as a tea tree but even still, kanukas and manukas are very different trees.
Kanuka is a finely textured, hard and heavy wood but it is slow to dry after becoming wet and tends to separate or crack. Kanuka is somewhat limited in use – you won’t see it used in flooring – since the timber is smaller and shorter than many other trees that grow significantly larger.
Kanukas tend to grow around 1m per year when young when furthers their reputation as a fast-growing shrub.
Kanuka is a fast growing tree which is another reason it’s abundant and easily used as firewood. Kanukas are also self-sowing which means they easily spread their seed on the ground leading to more of them growing over time, hence their reputation as being insidious.
What uses do kanuka trees have?
Kanuka is still grown for timber and firewood and also produces both honey and essential oils. In fact, kanukas tend to yield more oil than manukas do. Specialized equipment and skill is required for kanuka oil distillation however.
Kanuka oil is considered to be lighter and have smaller molecules than manuka and thus more easily penetrates the skin. It is further believed that regional differences throughout New Zealand can cause kanuka oil to have slightly difference properties depending on where it was grown i.e. different aroma, texture, color and clarity.
Like manukas, kanuka tends to be too small for use for furniture so its viability in this regard is somewhat limited.
In more environmental terms, kanukas have a reputation for growing over top of other trees and acting as shade as they grow. Eventually many larger trees will outpace kanukas and end up towering over them, often killing them off as the kanukas become shielded from the sun’s rays.
How does kanuka honey compare to manuka honey?
Other than the fact that manuka honey contains methylglyoxal which kanuka does not, both honeys have a pleasant taste in addition to offering potential health benefits. Kanuka has antimicrobial and anti-inflammatory properties due to its relatively high hydrogen peroxide content.
In terms of taste, kanuka honey is described as tasting lighter and floral whereas manuka is stronger with a richer floral taste.
Researchers
have discovered the potential benefits of kanuka honey specifically with regards to their “inflammatory response associated with wound healing.”
While manuka honey is well-known for its potential medicinal benefits due to its MKO and DHA (dihydroxyacetone) content, kanuka honey contains arabinogalactan (AGP) protein which stimulates the immune system, assisting our body to recover faster and better resist infections.