This is actually quite a complex subject ! and as with every other aspect of Eucalyputs there is conflicting or confusing information
All Eucalyptus leaves contain oil, though only twenty varieties have enough oil to be commercially viable, and ten make up the majority of global Eucalyptus oil production, and these can be grouped into three distinct categories:
- Medicinal for which the oil has a high content of cineole
The oil from different varieties is of different molecular structure. They may smell similar, the distinctive smell when you crush up Eucalyptus leaves, but those of different varieties are unique, though within the same variety the oil is very consistent.
I have a wide range of varieties planted in my mini forest, and each variety does have a unique smell when you crush up the leaves.
Since the birth of the Eucalyptus oil industry in the mid eighteen hundreds in Australia, Eucalyptus Globulus (Blue Gum) has been the dominate variety and currently makes up most of the world production with plantations in the Americas, Europe, Africa and Asia as well as the native Australia.
- Eucalyptus Polybractea (Blue Mallee)
This is not considered to be a suitable variety for Ireland. In it’s native range the lowest temperatures are around 3℃
- Eucalyptus Radiata (Narrow leaved peppermint)
This variety has been trialed in Ireland with good survival rates.
- Eucalyptus Dives (Broad leaved peppermint) NOTE there are several subspecies of Dives and although their appearance is similar, the oils produced are distinctly different !
Information on the specific oil producing properties is hard to come by. I haven’t found any information relating to Irish plantations.
- Eucalyptus Australiana, another in the genius of narrow leaved peppermint. Also one with subspecies which produce oils of different constituents.
I couldn’t find any specific information relating to frost tolerance or wind resilience.
- Eucalyptus Globulus does grow well in Ireland, and I have several in my personal mini forest here in West Clare. They are frost tolerant and wind resilient.
Cinerea has also been exploited for medicinal Eucalyptus oil.
- Eucalyptus Citriodora (Lemon Scented Gum) As the name suggested this is definitely one for those wishing to grow to produce essential oils for the perfumery market.
NOTE however that this is not a frost hardy variety
Macarthurii has been grown for perfumery Eucalyptus oil, and I have found them to be very hardy and wind resilient.
So far as I can make out, no Eucalyptus varieties are currently grown specifically to produce industrial oils, rather they are manufactured from a blend of oils from other varieties.
Uses for industrial Eucalyptus oil are:
- Bioenergy fuels
Though there is little detailed information available.
Sources and links