Essential oils, traditional uses and cultivation of Minthostachys (repost from old website)

I am considering to retire my Minthostachys website, but it would be good to have some of the information still available on the internet. The genus is, after all, of some cultural and economic significance to the people of the Andes. This is therefore one of a series of posts transferring previously written texts from the aforementioned website. Please disregard unless you are interested in this particular genus.

Essential oils found in Minthostachys

As other members of the mint family, Minthostachys plants produce various essential oils. These chemical components can have medical properties, or they are simply used in cooking, tea brewing or perfumery because of their pleasant taste or smell. Please note that I am not a biochemist myself and have simply composed the following list of the most relevant oils and their properties from biochemical studies of the genus conducted by other researchers. The exact oil composition is also subject to a high variability between and even within individual species, although oils rich in pulegone and menthone appear to be quite frequent.

Pulegone

One of the most important components of many Minthostachys oils, but it is best known from pennyroyal (Mentha pulegium). It is highly toxic in larger quantities, damages the liver and can induce abortion. Its toxicity probably explains some of the effect of the Minthostachys oil against pests and parasites. The substance is also used in perfumery and flavoring.

Menthone

Another very important component, together with pulegone often accounting for more than 75% of the entire oil composition. Best known from the peppermint (Mentha x piperita). It has a very pleasant minty aroma and is used in perfumery, but also has digestive properties.

Carvacrol

This and the next substance have been found to be dominant components in a lower proportion of studies of Minthostachys oils. Carvacrol is also found in various other well-known herbs like oregano (Origanum vulgare), summer savory (Satureja hortensis) or wild thyme (Thymus serpyllum), and is mostly valued for seasoning - the typical Pizza taste!

Carvone

As the name suggests, this substance is familiar as a product of caraway (Carum carvi), an Apiaceae. It has digestive properties and is used for flavouring.

Menthol

Perhaps the most important and well-known essential oil of the mints, especially Mentha arvensis (the source of japanese mint oil) and peppermint. It is usally much less important in Minthostachys, but sometimes found as minor component of the oil mixture. It is cooling and numbs pain, and is used against throatsore.

Linalool

Employed for seasoning and as an insecticide, Linalool is better known from coriander (Coriandrum sativum) of the Apiaceae. It is often one of the minor components of Minthostachys oil.

Thymol

As the name suggests, this substance is well known from the oils of various species of thyme (Thymus). It works as an antiseptic and against throat sore and coughing. It is sometimes found as a minor component in the oil of Minthostachys.

Other minor components include Limonene, Sabinene and Pinene, among others.

Traditional uses

The traditional uses of Minthostachys are manifold, but the most important are consumption as tea, seasoning, or medicinal infusions against various ailments of the digestive or respiratory systems. The first include cough, cold, flu, and similar, the second everything from stomach ache to diarrhea. Less frequently the plants are said to be used externally for other parts of the body, e.g. against rheumatism or bruises.

Other often-cited uses of these plants employ the aromatic odor of the leaves to repel various pests and parasites. Sweeping the floor with Minthostachys branches is said to rid the house of fleas. More importantly, campesinos especially in southern Peru and parts of Bolivia use Minthostachys and related, similar aromatic plants to preserve stored tubers. In storage, layers of potatoes or oca are alternated with layers of aromatic leaves to keep pests away. The oil-saturated atmosphere also inhibits tuber bud growth. Still, Argentina is certainly the country where the greatest amounts of Minthostachys are harvested and consumed. The local species, commonly called peperina, is nothing less than a cultural icon of Córdoba and well known throughout the country.

Cultivation

For large scale cultivation in Latin America, there exists a useful online resource from Argentina.

Several times already I have been asked if I knew a source of seeds or Minthostachys plants in Europe or North America, usually by people interested either in the traditional medicine of the Andes or in aromatic plants in general. Unfortunately, I am not aware of any company selling Minthostachys seeds. If one of my readers should find such a source, I would very much like to learn of it, so that I can circulate this information. For those who actually want to try their luck with the cultivation of a plant in temperate climates, I would like to give the following advice, which is a slightly rewritten version of what I recently answered to such a question:

Minthostachys has evolved under a climate in which the major temperature oscillations occur between day and night, and not between summer and winter as in a temperate climate. This means that the more hardy species might just survive a night of frost if followed by a warm day, but never three continuous months of winter. My best advice would be to cultivate it in the garden during summer and put it into a cool but frost-free place in winter; preferably a cool greenhouse like those used for bringing Mediterranean plants through the winter, or perhaps something like a bright but relatively unheated corridor in the house. After some time, one could produce another plant from a cutting as a backup, and start to experiment with leaving one clone in a very protected place outside during winter, perhaps under an insulating cover of dry leaves or a glass plate. But I would not be very optimistic.

I must also warn that Minthostachys plants are not one of the easiest cultivars. They can be killed easily through insufficient drainage of the soil. If kept away from rain, as they would be in a greenhouse during winter, they tend to get red mites that damage the leaf epidermises. They are also regularly attacked by green caterpillars that are, in Eurasia and North America, really specialized on feeding on true mints (genus Mentha). It is likely that they recognize their food plants by scent and are attracted by the similar essential oils. Although I obviously understand why some people in the northern hemisphere would like to have this specific genus in cultivation - I love it myself, after all - for all practical as opposed to emotional purposes it seems easier to cultivate the pennyroyal Mentha pulegium instead, as it is hardy and has a quite similar essential oil composition.

If you are traveling through South America and want to make sure you see a Minthostachys without searching in the wild, there are some local botanical gardens that have them in cultivation. I know that the botanical garden of the Universidad Mayor de San Andres of La Paz, Bolivia, has at least one plant of Minthostachys acutifolia, and that the large botanical garden of Bogotá in Colombia has some impressive Mintostachys mollis shrubs in its medicinal plants section (see photo above).