Tarragon is one of many Artemisia species with a storied past.  Jeanne introduces you to her favorite genus. 

If you love eating French food, and especially if you love cooking it, when you see a tarragon bush, inevitably you think of the French quartet fines herbes:  fresh parsley, chives, tarragon and chervil.  You may reminisce about a perfect (or broken) Béarnaise sauce.  These days when I pass my tarragon plant I vow to actually use it, as we’ve neglected it this year.  I also think of sagebrush.  And absinthe, martinis, and Shakespeare. And weeds, malaria, and hippies.  I attribute this motley mental association to tarragon’s membership in my favorite genus, Artemisia, a large group in the composite (sunflower) family, Asteraceae, with a rich history.

The grey shrubs are big sagebrush (Artemisia tridentata), in Yellowstone National Park.

My love affair with the genus began long before I ever learned how to cook with tarragon.  My Proustian madeleine is the fragrant smell of big sagebrush (Artemisia tridentata) after rain, always triggering happy childhood memories of my grandmother’s pasture in Wyoming.  Her pasture probably contained at least another of the dozen(ish) sagebrush species inhabiting the American West as well as some herbaceous Artemisia species, like white sage (A.ludoviciana).  Boasting around 400 species, Artemisia is one of the largest genera in the sprawling Asteraceae.  Its complex biogeographic history in the mid- to high latitudes of the Northern Hemisphere is still being worked out.  Different species have migrated from the central Asian origin of the genus to western Europe and the Americas and back again multiple times, radiating into their own little clades each time, leading to a complicated phylogeny in which some sister groups are now native to different continents (see phylogeny below)(1).  Woodiness evolutionarily waxes and wanes within the genus as the species colonize new areas.

Phylogenetic relationships among some Artemisia species. Red branches indicate native North American species; black bars indicate native European and Asian species (although A. dracunculus spans both continents).  Data from (1).

Like wild Brassica oleracea many Artemisia species are composed of large and diverse assemblages of populations.  As the group’s evolutionary history is reconstructed, biologists will likely redraw species lines.  For example, the native range of wild tarragon (A. dracunculus) spans western North America and much of central Asia and Europe.  Some populations are spicy, like the culinary tarragon, but most are not.  Some populations even have different chromosome numbers, a big clue that a single species name hasn’t been appropriate for this group for a long time (2, 3).  Despite being commonly called “French” tarragon, 13^th century Mongolian traders likely brought the spicy herb to the attention of Western Europe.

French tarragon (photo by K. Preston)

This particular cultivar is actually sexually sterile (due to the same genetic slipperiness that leads to populations with different chromosome numbers) and can only be propagated through cuttings and root division.  This apparently has been the case since its early introduction to the Western palate, cuttings handed down generation after generation, directly connecting the tarragon shrubs in modern gardens to the Silk Road.  If you plant “tarragon” seeds, you’ll get an attractive plant but not a tasty herb.  In fact, you’ll probably find it quite bitter, as almost all the species are.  The medicinal value of these bitter compounds has made many Artemisia species popular as tonics and medicine throughout recorded history. The genus is still in the modern pharmacopeia.  And the liquor cabinet.

Mugwort (Artemisia vulgaris) growing with Queen Anne’s lace and grasses

The weeds-malaria-and hippies part of my mental association is reinforced almost daily from spring to fall by the abundance of weeds Sweet Annie and mugwort near my house.  Annual Sweet Annie (Artemisia annua) (http://www.johnnyseeds.com/p-6084-sweet-annie-og.aspx), native to China but now a longtime resident of much of the world, is the original source of the potent anti-malarial compound artemisinin.  Unfortunately some populations of the malaria plasmodium are already resistant to artemisinin, but the compound is still widely used in concert with other anti-malarial drugs.  Many species of Artemisia produce artemisinin, but A. annua seems to be the most common plant to reliably make the most of it.  Chemically artemisinin is similar to the bitter white latex compounds in fellow composites lettuce and chicory, and to ascaridole that lends flavor to distantly-related culinary herbs epazote (Chenopodiaceae) and Chilean boldo (Monimiaceae).

California sagebrush (Artemisia californica), with small flowers typical of the genus (photo by K. Preston)

Mugwort (Artemisia vulgaris) is another Eurasian native turned cosmopolitan weed. It was traditionally used as a medicinal “wormwood” (vermifugal) herb and in beer brewing, to add bitterness before using hops became popular.  Either A. vulgaris of any of another handful of annual Artemisia species (especially A. argyi) is used in traditional Chinese medicine both as a wormwood and for moxibustion, in which the dried herb is burned on or near the skin.  When I see mugwort I remember the boxes of moxa, rolled dried mugwort leaves, lining the shelves of the Chinese herbal medicine store attached to a yoga studio I used to go to in grad school with a friend of mine.  My friend would always point to the boxes, recalling a free-spirited practitioner in Vancouver who used to treat her with it.  Like many Artemisia species, mugwort smells great. I love to pick a leaf off of mugwort plants as I walk by them, crush it and inhale its fragrance.  Especially because I currently live thousands of miles away from  sagebrush, the smell of mugwort, reminiscent of that of its cowboy cousin, is certainly a welcome small medicine.

Southernwood (Artemisia abrotanum) shrub in the Monticello garden, used as medicine and for fragrance in Jefferson’s time

Speaking of welcome medicine, although anise dominates the flavor of the liqueur absinthe, the Mediterranean shrub A. absinthium that also bears that name is responsible for its reputation.  According to Amy Stewart’s excellent book The Drunken Botanist, millenia before the alcoholic tincture of this wormwood and other herbs became a bohemian icon, like other Artemisia species, it was used as a medical treatment, especially for intestinal worms (4).  A. absinthium and many other European and Asian Artemisia species were brewed into a number of spirits as medicine.  Fortified wine with A. absinthium eventually became vermouth, hence the tarragon-martini mental connection.  In the Alps the Artemisia species are collectively referred to as génépi, and any number of them (including the two in the phylogeny diagram) may become a génépi liqueur.

The most dramatic historical accounts of the hallucinogenic effects of drinking absinthe probably are more attributable to its high alcohol content or poisonous adulterations than to the wormwood itself.  Many Artemisia species, though, do have a psychoactive reputation in herbal medicine.  Mugwort, for example, reputedly delivers pleasant dreams and induces clarity of mind and vision.  With this in mind, some Shakespearean scholars think that an Artemisia must be the “Dians bud” in A Midsummer Night’s Dream, the herb that Oberon uses to restore the confused revelers to their right mind (5).  “Dians” likely comes from Diana, the Greek name for the Roman goddess Artemis, who according to mythology gave humanity her namesake wormwoods.

French tarragon shrubs

One of the many defensive compounds in Artemisia, thujone, was blamed for a time for the supposed dangerousness of Artemisia liqueurs, but this has been discredited.  A tarragon béarnaise sauce probably has as much of the stuff as a serving of absinthe, a tiny and definitely not dangerous amount in both cases.  Whether medicinal or not, Artemisia species readily release their flavorful compounds into alcohol, vinegar or fat.  Folks whose opinions about food are worth listening to disagree about the effect of drying the Artemisia herbs (especially tarragon) on flavor:  some think the dried herb is worthless, some think it may even be superior to the fresh. I haven’t determined my preference yet for fresh or dried tarragon in the kitchen.  Well, the fines herbes blend I think must be used fresh, but for a butter sauce or a tarragon vinegar?  I need to experiment.  Clearly, all such experiments will best be accompanied by an Artemisia-laced cocktail.

References

1.         Watson LE, Bates PL, Evans TM, Unwin MM, & Estes JR (2002) Molecular phylogeny of Subtribe Artemisiinae (Asteraceae), including Artemisia and its allied and segregate genera. Bmc Evol Biol 2.

2.         Eisenman SW & Struwe L (2011) The global distribution of wild tarragon (Artemisia dracunculus L.; Asteraceae) cytotypes with twenty-seven new records from North America. Genet Resour Crop Ev 58(8):1199-1212.

3.         Kreitschitz A & Valles J (2003) New or rare data on chromosome numbers in several taxa of the genus Artemisia (Asteraceae) in Poland. Folia Geobot 38(3):333-343.

4.         Stewart A (2013) The drunken botanist: the plants that create the world’s great drinks.  (Algonquin Books of Chapel Hill,, Chapel Hill, N.C.).

5.         Vlasopolos A (1978) Ritual of Midsummer – Pattern for a ‘Midsummer Night Dream’. Renaissance Quart 31(1):21-29.