Common Name: Mānuka

General Information

Leptospermum scoparium is a very variable evergreen shrub or a small tree that usually grows around 2 metres tall but can reach 5 metres[, ].
A multi-purpose and very useful tree, it is harvested from the wild and also encouraged to grow in order to provide food, medicines and a range of materials. It is especially valued for its essential oil, which is used medicinally, in cosmetics etc, and also for the honey (known as manuka honey) obtained from its flowers. It is sometimes allowed, or even encouraged, to grow in meadows in order to provide food for hive bees and produce manuka honey[]. The plant is an excellent pioneer for re-establishing woodlands, it is used in soil stabilization projects and is commonly grown in amenity plantings and as an ornamental in gardens.
Leptospermum scoparium is a natural pioneer species, quickly appearing in disturbed areas in forests in New Zealand. Its seeds are light, wind-dispersed and numerous, they germinate in bare patches, and the plant grows quickly, establishing dominance over low-growing vegetation. They create a good environment for other forest trees to become established and then usually die out after about 60 years as these larger, longer living trees overshadow them. However, in impoverished or wet soils, the plant can become the dominant climax vegetation.The planIt has escaped from cultivation in some areas and is seen as a possible threat to the native flora in S. Africa and Hawaii[].

Known Hazards

None known

Botanical References

, ,

Range

Australia - Tasmania, Victoria, New South Wales; New Zealand

Habitat

Many habitats in lowland to alpine areas, North, South, Stewart and Chatham Islands[]. Rocky and sandy heathland, often by streams[]. Occurs along banks of watercourses and on lower hillslopes, often in rocky sites[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	5.00 m
Growth Rate	Medium
Pollinators	Insects
Cultivation Status	Ornamental, Semi-cultivated, Wild

Cultivation Details

Leptospermum scoparium is not a very cold-hardy plant, able to tolerate short periods with temperatures down to around -10°c when fully dormant[, ].
Succeed in almost any neutral or acid soil of good or reasonable quality[], preferring a light sandy loam and full sun[]. Succeeds in dry soils. Prefers a position sheltered from hot or cold drying winds. We have found the plants to be fairly tolerant of maritime exposure[].
A polymorphic species[].
Often grown as an ornamental, many forms have been developed for their ornamental value[]. These include some dwarf varieties that grow very well in pots in cold greenhouses and conservatories[].
Resents root disturbance[].
Plants do not regenerate from old wood[].
The bruised leaves and the flowers are pleasantly aromatic[, ].
Plants in this genus are notably resistant to honey fungus[].

Edible Uses

The fresh, pungent leaves are a fragrant and refreshing tea substitute[, , ]. Of excellent quality, in taste trials this species has often received higher marks than the traditional China tea obtained from Camellia sinensis[]. It is important to brew the leaves for considerably longer than normal teas to ensure the flavour is released into the water[].

A sweet manna is sometimes exuded from the stems as a result of insect damage[, , ]. It has been used as a food for infants[].Another report says that manna is reported to form on the leaves[].

Medicinal

An essential oil obtained from the plant has vermifuge and anti-bacterial properties[]. It is used in the treatment of many conditions, especially those affecting the skin[]. It is sold in New Zealand and many other countries[].

An infusion of the leaves and bark has been used in the treatment of various ailments[].

A manna that sometimes exudes from the stems has been used to treat coughs[].

Manuka honey is a very old and effective remedy for bacterial infections and is also a very popular honey[].

Agroforestry Uses:

This species can be grown as a hedge and is reasonably tolerant of maritime exposure. Plants should not be trimmed back into old wood, however, because they do not regenerate from such treatment[].
It is an important pioneering plant in New Zealand[]. It naturaly invades areas of disturbed soil, germinating quickly and rapidly producing a dense cover that excludes grasses and allows native forest trees to become established. As these forest trees grow taller, they gradually out-compete and eliminate the Leptospermum over the course of about 60 years[].
It is excellent for revegetating bare, eroded slopes and can grow on poorer, colder, wetter and more acidic sites than kanuka (Leptospermum ericoides)[]. Another advantage of planting manuka for soil conservation is that browsing animals like sheep, cattle and goats don't often eat it[].
Leptospermum scoparium is a major source of honey harvested by the introduced honeybee (Apis mellifera) and the production of manuka honey has become a major industry both in New Zealand and elsewhere. Although many honey types have antibacterial properties because of the presence of hydrogen peroxide, only manuka honey has a high level of non-peroxide anti-bacterial activity. This non-peroxide antibacterial factor has been named Unique Manuka Factor (UMF). Manuka honey is now used in many medical products in many countries[].

Other Uses

A yellow-green dye is obtained from the flowers, branches and leaves[].
A greenish-black dye is obtained from the flowers[].

An essential oil obtained from the plant is insecticidal[, ].

The essential oil obtained from the leaves and branches is used as an ingredient in commercial cosmetic preparations as a tonic[].
An extract of the leaves is used as an ingredient in commercial cosmetic preparations as a skin conditioner[].
An aqueous solution of the steam distillate obtained from the branches, flowers and leaves is used as an ingredient in commercial cosmetic preparations as a masking agent[].

The bark was used for making water containers and the inner bark as a waterproof layer for roofing[]. The bark is used for roofing huts[].

The red wood is strong and elastic. It is used for inlay work, cabinet making, tool handles, fencing etc[, , ].
The wood is highly valued and much used as a fuel and to make charcoal[, ]. It burns extremely hot and slow and is probably the best native firewood in New Zealand[].

Propagation

Seed - sow spring in a greenhouse and only just cover the seed. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse for at least their first winter. Plant out in late spring or early summer, after the last expected frosts, and give some protection from the cold for their first winter or two outdoors. The seed remains viable for many years.
Cuttings of half-ripe wood, 5 - 8 cm with a heel, early August in a frame. Over-winter in the greenhouse for its first year. Good percentage[].
Cuttings of almost mature wood, 4 - 5 cm with a heel, autumn in a frame. Good percentage[].