Sunday, June 16, 2024
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Tea Tree

tea-treeTea Tree is an exciting essential oil for Cape Mountain Oils .  This plant is indigenous to Australia and the oil is imported into South Africa in large quantities. Very little essential oil is currently produced in the country, and we are unaware of any other organically certified producer of the oil in South Africa.  Despite our harsh conditions, the early indicators are that this plant will do well, provided that it is well managed.    We currently have 3 000 plants in the ground under drip irrigation.

Tea Tree (Melaleuca alternifolia) is a relative of the Eucalyptus and occurs naturally along valley floors on the north coast of New South Wales and into Queensland.  It is an attractive thin-leafed plant with soft, fine branchlets.  If left to its own devices, it can grow into a substantial tree and there are impressive stands of tea tree occuring naturally in Australia.  When flowering it produces a dense cotton-wool like mass of sticky white florets.  Given that the plant is not indigenous, we do not allow seed shot to take place and we harvest soon after flowering has subsided.  Harvesting is rigorous and the plants respond to pruning.  We do not allow the plants to grow beyond 2 metres in height and planting is dense (at 0.5 m in row by 0.7 between rows).  This density is not recommended by Australian producers, who grow the trees to far greater heights and harvest mechanically.   As we harvest by hand, we have opted to retain the plants at a manageable size and to harvest annually, rather than to wait until the tree is fully established.  We harvest at 50 cm above ground to allow for regrowth, although the plant can be cut as low as 15 cm above ground.

tea tree seedlings
Tea tree is a relatively new plant to be cultivated in South Africa and there appears to be some contradiction between the Australian experience and the recommendation of our agricultural authorities.  The South African recommendation is a planting density of 12 000 plants per hectare, while the Australian industry attains a density of 30 000 - 40 000 plants per hectare: despite this large difference, the South African authorities estimate a plant material yield of 26 tons per hectare whilst the Australians anticipate lower yields.  Both authorities accept an anticipated oil yield of 1 %.  It remains to be seen precisely what plant material yield and planting density we are able to achieve on Rockhaven.

The plant has high water needs (often growing in sodden land in Australia), although the nutrition recommendations vary massively between Australia (where recommendations are low) and South Africa (where ARC receommends high nitrogen applications).  We are experimenting with different applications to assess the correct nutrition requirements of the plants.  Water is provided through high volume drip (we run most essential oil plants at 2,3 litre per hour, whilst we are running the Tea Tree at over 3,5 litre per hour); water is also given more often than the other plants under production.  Mulching (using wood chips produced on the farm and old hay from a nearby dairy) is also essential to keeping the root area moist and cool.

Propogation is difficult, as cuttings have not proved to be successful.  Seed propogation is being attempted, but for the moment we have purchased our plants as seedlings from a producer in Gauteng. 

The oil is a light straw-coloured oil and yield is presently as anticipated (around 1 %), although we need to go through a few more seasons to establish precise yield figures.  Tea tree oil must conform to certain standards in order to be acceptable for use in the cosmetic, health care and toiletry industries.  The oil contains cineole, which at certain levels can be a skin and mucouos-membrane irritant.  Pharmaceutical standards require cineole content to be below 5 %, while commercial standards require cineole to be below 15 %.  Terpene-4-ol should be above 30 %.   Tea tree has valuable antiseptic qualities which are active against common bateria and fungi.  It is used in a wide variety of treatments, including effective management of ring worm and the antiseptic contorl of burns.  The market for locally produced, organic Tea Tree oil is not yet established, although the oil is very popular with the public.

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