There are multiple varieties of lavender used for medicinal essential oils. True lavender (Lavandula angustifolia) is the most common species harvested for its essential oil, and has been in use for thousands of years. True lavender grows at altitudes above two thousand feet, and has been used historically to treat throat infections.
Spike lavender (Lavandula latifolia) was traditionally used for headaches, rheumatic pain, colic and dyspepsia. It grows at lower altitudes than true lavender and has a very high yield. Spike lavender has gray-blue flowers, and is mainly grown in France and Spain for essential oil use.
Lavender as a species, and within the species, varies from plant to plant and from oil to oil due to factors such as climate, environment, altitude grown at and country of origin. However, each type of lavender oil does carry a similar chemical make-up. The main chemical constituents of lavender are as follows:
- Lavandula angustifolia – predominately esters and alcohols
- Lavandula stoechas – predominately ketones (the high amounts of ketones is why this type of lavender is usually avoided in aromatherapy.)
- Lavandula latifolia – predominately oxides, alcohols, followed by ketones and monoterpenes
- Lavandula x intermedia – predominately alcohols and esters.