Leptospermum
| Leptospermum | |
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| Leptospermum squarrosum | |
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| Genus: | Leptospermum |
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Leptospermum /ˌlɛptəˈspɜːrməm, -toʊ-/[2][3] is a genus of shrubs and small trees in the myrtle family Myrtaceae described as a genus in 1775.[4][5] Most species are endemic to Australia, with the greatest diversity in the south of the continent; but one species extends to New Zealand, another well into Southeast Asia, and L. recurvum is found only in Malaysia and Indonesia.[1]
They are shrubs or occasionally small trees, reaching 1–8 m (3–26 ft) tall, rarely up to 20 m (66 ft), with dense branching. The leaves are evergreen, alternate, simple, sharp-tipped, and small, in most species not over 1 cm long. The flowers are up to 3 cm diameter, with five white, pink or red petals.
Uses
The common name tea tree for the Leptospermum species derives from the practice of early Australian settlers who soaked the leaves of several species in boiling water to make an herbal tea rich in ascorbic acid (Vitamin C).[citation needed]
The nectar from the flowers is harvested by bees; this is used to make Leptospermum honey. Honey produced from Australian Leptospermum polygalifolium, also known as jelly bush or the lemon-scented tea tree, has been found to contain up to 1750 mg/kg of 'methylglyoxal' (MGO), an antibacterial compound.[6] However, after neutralization of this compound, the "manuka" honey retains bactericidal activity.[7] Methylglyoxal thus does not appear to be the main contributor to the antimicrobial and antibacterial activities.[8]
In Australia, Leptospermum species are sometimes used as food plants by the larvae of hepialid moths of the genus Aenetus, including A. lewinii and A. ligniveren. These burrow horizontally into the trunk then vertically down.
Most Leptospermum species make desirable garden plants. The hardiest species (L. lanigerum, L. liversidgei, L. polygalifolium, L. rupestre, L. scoparium) are hardy to about −8 °C (18 °F) to −10 °C (14 °F); others are sensitive to frost. They tolerate most soils (but many supplies specify ericaceous (i.e. lime-free) compost) and exposures with good drainage and full sun. Established plants are drought tolerant. They are often found as hedge plants on the west coast of the United States, and some species are popular for cultivation as bonsai. Many cultivars exist.
- General Use
These flowers are also grown in double cultivars and are used in floral designs. However, they do not last when out of water and the single flowers do not last when wired. The 'Pacific Beauty' (Leptospermum poolgalifolium) is a useful flower to use in large church-service bowls and function arrangements, however use of Leptospermum in corporate designs is less desirable as they dry and drop when subjected to heating and air conditioning.
Species
- accepted species[1]
References
- ^ a b c Kew World Checklist of Selected Plant Families
- ^ "Leptospermum". Dictionary.com Unabridged (Online). n.d. Retrieved 2016-01-21.
- ^ Sunset Western Garden Book, 1995:606–607
- ^ Forster, Johann Reinhold & Forster, Johann Georg Adam. 1775. Characteres Generum Plantarum 71–72, pl. 36
- ^ Tropicos, Leptospermum J.R. Forst. & G. Forst.
- ^ Native honey a sweet antibacterial, Australian Geographic, March 3, 2011.
- ^ Kwakman PHS; te Velde AA; de Boer L; Vandenbroucke-Grauls CMJE; Zaat SAJ (2011). "Two major medicinal honeys have different mechanisms of bactericidal activity". PLoS ONE. 6 (3): e17709. doi:10.1371/journal.pone.0017709. PMC 3048876. PMID 21394213.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Molan, P. (2008). "An explanation of why the MGO level in manuka honey does not show the antibacterial activity". New Zealand BeeKeeper. 16 (4): 11–13.
