11 Nov

Varieties

 An Introduction to Lavender, or Genus Lavandula

Lavenders belong to the Lamiaceaea family (or “Mint” family), along with many herbs such has basil, oregano, marjoram, mint, thyme, sage and others.  There is considerable confusion and misinformation about lavender classifications and names floating around the internet and even in print, and I reference the information in this summary to the United States Department of Agriculture (as to the taxonomy of lavender) and to the seminal work of Virginia McNaughton, author of  “Lavender: the Grower’s Guide”, widely regarded as the authoritative botanical varieties1reference on lavenders.  I think it’s important to have a general understanding of lavender varieties, because it’s very insightful as to the value of the lavender products and essential oils we look to purchase, and lavender species can vary greatly in the efficacy of their essential properties and in the quality of their perfumes.  We are often comparing lavender products and prices that are apples to oranges, and this brief discussion provides insight into how to find the best quality lavender products and oils that, thankfully have the most wonderful fragrances combined with the most powerful essential properties.  The genus Lavandula includes over 30 species of small shrubs or herbs that were grouped into the following six sections:

  1. Lavandula (formerly Spica), native to the Mediterranean region, France in particular (4 species);
  2. Stoechas, native to the Mediterranean region (1 species);
  3. Dentata, native to the Mediterranean region, Macronesia and southwards to Arabia (1 species);
  4. Pterostoechas, native to North Africa and Macronesia (15 species);
  5. Chaetostachys, native to India (2 species); and
  6. Subnuda, native to Arabia and adjacent parts of Africa (8 species).

Under the Biological framework we call the Classification of Living Things, the order is as follows:

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species → Cultivar

The correct taxonomy for a specific lavender plant variety would be as follows:

Eukarya → Plantae (Tracheobionta) → Spermatophyta (Magnoliophyta) → Magnoliopsida (Asteridae) → Lamiales → Lamiaceae → Lavandula → Angustifolia → Buena Vista

It’s important to know that each of the 30+ species within the Genus Lavandula can have hundreds of cultivars (although some may have only a few). You can also see that the six sections are simply helpful groupings of species, and are not actually listed in the taxonomy of a specific lavender plant.

Brief Overview of the Six  Sections

varietiesLavandula is what we are concerned with, as virtually all lavenders we know and love come from this section although to a lesser extent, Stoechas are available and enjoyed.  Stoechas are sometimes referred to as “Spanish Lavenders”, but also “French Lavenders” or “Italian Lavenders” (and what we believe the Romans used to make wine and in their famous baths), and don’t yield as much essential  oils or buds like the Lavandulas, but are considered by some to be the most beautiful lavenders.  Dentata is a very recent section, carved out of the Stoechas in 1996 after botanists finally all agreed a small group of these plants didn’t hybridize readily within the other Stoechas because they really are a bit different (if you care to compare bracts and peduncles).  This makes Dentata an interesting, but obscure section.  Pterostoechas, which means “winged stoechas” contains 15 species.  Some of these species are in cultivation throughout North Africa and Macronesia.  They are purported to have quite a different fragrance than the other lavenders (not as prized as Lavandula).  The section Chaetostachys contains only two species that are native to central and southern India.  They are considered rare, and again not very relevant to the discussion of lavenders in cultivation.  The last section, Subnuda, contains eight species grown in South Arabia and tropical Africa, and their leaves appear almost like a thistle or fern and mature plants are totally naked of leaves (hence the latin name).  The Subnuda species are also rare in cultivation.

Section Lavandula

Now we get to the lavenders we recognize and love, within the Lavandula section.  This section contains a wide range of lavenders, from those commonly referred to as “English Lavenders” and “French Lavenders” and have the most prized fragrances of any lavender plants known to man, to those lavenders with harsher fragrances that are used to make ceramic paint.

There is a history of confusion for the names of this section, which I’ll try to keep simple here.  The reason all this confusion regarding nomenclature is important is because today many inferior quality lavender products and essential oils are sold to an unsuspecting public.  There is a vast difference between the highest quality essential oils, used in the perfume industry, and the lowest quality essential oils, often packaged and sold as lavender but also used for industrial purposes.  This section of lavender was formerly known as Spica, causing confusion with what now is commonly  (and erroneously) referred to as Spike Lavender (but Spike lavender, and you can buy essential oil labeled as Spike even today in natural markets, is actually one of the Lavandula section’s species correctly named Latifolia which is not the highest quality oil).   Here are the four Lavandula species:

  • Lavandula: Angustifolia
  • Lavandula: Latifolia (Spicus)
  • Lavandula: Lanata
  • Lavandula: x intermedia

varieties3The Lavandula: Angustifolia  species contain the most prized lavender varieties, and many know of these varieties as English Lavenders and French Lavenders.  Angustifolias were, in times past, known as Lavandula: Vera (true lavender), Lavandula: Officianalis (official lavender), and Lavandula: Spica (just to throw Spike in there at another level, goodness).  We happen to grow 15 of these Angustifolia varieties at our farm in Southern Oregon.  All of the Angustifolias are considered edible lavenders, and contain the most fragrantly scented lavender perfumes.  When you buy lavender products, and especially lavender essential oil, you want it to be an Angustifolia variety blend.   Angustifolia essential oil is superior in both fragrance and therapeutic properties and it can be expected will be priced at a premium.  Virtuallly all clinical and medical studies performed on the therapeutic benefits of lavender use Angustifolia essential oil.  It is the gold standard of lavenders.

The Lavandula: Latifolia species is what is commonly mistaken as  Spike lavender.  Unlike the very bushy, compact Angustifolia plants, the Latifolia varieties have lower compact leaves but the stems grow very tall and have branches that “spike” out (hence the name).  They are quite distinctive and easily recognizable because of this feature.  Latifolias grow larger, are vigorous and have higher essential oil yields.  Most important to us, the modern users of lavender, the Latifolia varieties are hallmarked by a much harsher fragrance, that while not unpleasant, is often used in ceramic paint and for other industrial purposes.  Interestingly, Latifolia essential oil is sold (even at natural markets) under the name Spike, and most people that are purchasing and using the lavender may not be aware that what they are purchasing, smelling and using is not the wonderful so-called “true lavender”, the sister species Angustifolia.  Latifolia essential oil is inferior to Angustifolia essential oil and should be priced considerably lower.

The Lavandula: Lanata species is commonly known as “woolly lavender”, so called because the leaves of this plant are silvery grey and have a soft, velvety texture with long, matted hair.  The Lanata species are native to southern Spain, and really only are happy in very dry, well-drained conditions and don’t like to be transplanted.  This species is rare in cultivation but is sought after for its beautiful foliage.

varietiesThe Lavandula: x intermedias are a very interesting group.  Intermedias, often referred to as Lavandins, are actually hybrids between the three other Lavandula species.  Principally it refers to hybrids between the Angustifolia and Latifolia species, and these lavenders are often referred to as “French Lavenders” (read on to see why).  Why would you hybridize these two?  The easiest way to answer this is to perhaps point to the most famous x Intermedia of all, the x Intermedia variety Grosso lavender.

Until 1920, all lavender used for essential oil was wild harvested. France took the lead on the commercial production of lavender essential oils, a natural fit since many Lavandula: Angustifolia varieties grew wild on its sunny, stony hillsides in the Provence region. Commercial production brought the blight of the so-called “yellow decline”, decimating crops. For this reason, various Lavandula: x intermedia varieties were developed to be resistant to Yellow Decline, eventually in the 1970s including the Lavandula: x intermedia cultivar, Grosso.  Grosso is the most widely grown lavender in commercial cultivation, because it’s a successful blend between the vigorous growth and size (and consequently high essential oil yield) of the Latifolia, but is softened by the fragrance characteristics of the Angustifolias.  This allows commercial growers to produce more essential oil from fewer plants, with an improved quality essential oil over the Latifolia (or Spike) lavenders in the marketplace (however, the Grosso essential oil is still quite camphorous when compared to the Angustifolia varieties).  Furthermore, the Grosso variety is more easily adapted to mechanical harvesting than other lavenders.

Most of the lavender essential oils sold are x Intermedias, and Grosso in particular, for this reason.  However, while they are a boon to large scale commercial growers, the quality of the fragrance notes and the therapeutic value of the essential characteristics of x Intermedias remain inferior to the prized Angustifolias.  We grow four varieties of x Intermedia on our lavender farm, including Grosso.


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