Leaf shape is diverse across the genus. They are simple in some commonly cultivated species; in other species, they are pinnately toothed, orpinnate, sometimes multiple pinnate and dissected. In most species, the leaves are covered in fine hairs orindumentum, which normally contain essential oils.[5]
Flowers are contained inwhorls, held on spikes rising above the foliage, the spikes being branched in some species. Some species produce coloredbracts at the tips of theinflorescences. The flowers may be blue, violet, or lilac in the wild species, occasionally blackish purple or yellowish. Thesepal calyx is tubular. Thecorolla is also tubular, usually with five lobes (the upper lip often cleft, and the lower lip has two clefts).[6]
One of the first modern major classifications was that of Dorothy Chaytor in 1937 at Kew. The six sections she proposed for 28 species still left many intermediates that could not easily be assigned. Her sections includedStoechas,Spica,Subnudae,Pterostoechas,Chaetostachys, andDentatae. However, all the major cultivated and commercial forms resided in theStoechas andSpica sections. There were four species withinStoechas (Lavandula stoechas,L. dentata,L. viridis, andL. pedunculata) whileSpica had three (L. officinalis (nowL. angustifolia),L. latifolia andL. lanata). She believed that the garden varieties werehybrids between true lavenderL. angustifolia and spike lavender (L. latifolia).[11]
SubgenusLavandula is mainly of woody shrubs with entire leaves. It contains the principal species grown as ornamental plants and for oils. They are found across the Mediterranean region to northeast Africa and western Arabia.
SubgenusFabricia consists of shrubs and herbs, and it has a wide distribution from the Atlantic to India. It contains some ornamental plants.
SubgenusSabaudia constitutes two species in the southwest Arabian peninsula and Eritrea, which are rather distinct from the other species, and are sometimes placed in their own genusSabaudia.
In addition, there are numerous hybrids and cultivars in commercial and horticultural usage.[5]
The first majorclade corresponds to subgenusLavandula, and the secondFabricia. TheSabaudia group is less clearly defined. Within theLavandula clade, the subclades correspond to the existing sections but placeDentatae separately fromStoechas, not within it. Within theFabricia clade, the subclades correspond toPterostoechas,Subnudae, andChaetostachys.
Thus the current classification includes 39 species distributed across 8 sections (the original 6 of Chaytor and the two new sections of Upson andAndrews), in three subgenera (see table below). However, since lavendercross-pollinates easily, countless variations present difficulties in classification.
subsp.stoechas — mostly coastal regions of east Spain, southern France, west Italy,Greece,Bulgaria, southern coastalTurkey, Levantine coast, and many Mediterranean islands.
subsp.luisieri — coastal and inland Portugal and border regions of Spain.
The English word lavender came into use in the13th century, and is generally thought to derive fromOld Frenchlavandre,[15] ultimately fromLatinlavare fromlavo (to wash),[16] referring to the use of blueinfusions of the plants for bathing.[10]: 35 The botanic nameLavandula as used byLinnaeus is considered to be derived from this and other European vernacular names for the plants.[17]
The names widely used for some of the species, "English lavender", "French lavender" and "Spanish lavender" are all imprecisely applied. "English lavender" is commonly used forL. angustifolia, though some references say the proper term is "Old English lavender".[18] The name "French lavender" may refer to eitherL. stoechas or toL. dentata. "Spanish lavender" may refer toL. pedunculata,[19]L. stoechas,[20] orL. lanata.
The most common form in cultivation is the common or English lavenderLavandula angustifolia (formerly namedL. officinalis). A wide range ofcultivars can be found. Other commonly grown ornamental species areL. stoechas,L. dentata, andL. multifida (Egyptian lavender).
Because the cultivated forms are planted in gardens worldwide, they are occasionally found growing wild as garden escapes, well beyond their natural range. Such spontaneous growth is usually harmless, but in some cases,Lavandula species have becomeinvasive. For example, in Australia,L. stoechas has become a cause for concern; it occurs widely throughout the continent and has been declared a noxious weed in Victoria since 1920.[21] It is regarded as a weed in parts of Spain.[22]
Lavenders flourish best in dry, well-drained, sandy or gravelly soils in full sun.[23] English lavender has a long germination process (14–28 days) and matures within 100–110 days.[24] All types need little or no fertilizer and good air circulation. In areas of high humidity, root rot due to fungus infection can be a problem. Organic mulches can trap moisture around the plants' bases, encouraging root rot. Gravelly materials such as crushed rocks give better results.[25] It grows best in soils with a pH between 6 and 8.[26] Most lavender is hand-harvested, and harvest times vary depending on intended use.[26]
A 2007 study examined the relationship between various fragrances andphotosensitivity, stating that lavender is known "to elicit cutaneous photo-toxic reactions", but does not inducephotohaemolysis.[30]
Commercially, the plant is grown mainly for the production of lavender essential oil. English lavender (Lavandula angustifolia) yields an oil with sweet overtones and can be used in balms, salves, perfumes, cosmetics, and topical applications.[7]
Lavandula× intermedia, also known aslavandin orDutch lavender, hybrids ofL. angustifolia andL. latifolia.[31] are widely cultivated for commercial use since their flowers tend to be bigger than those of English lavender and the plants tend to be easier to harvest.[32] They yield a similar essential oil, but with higher levels ofterpenes, includingcamphor, which add a sharper overtone to the fragrance, regarded by some as of lower quality than that of English lavender.
Culinary lavender is usually English lavender, the most commonly used species in cooking (L. angustifolia 'Munstead'). As an aromatic, it has a sweet fragrance with lemon or citrus notes.[33] It is used as a spice or condiment in pastas, salads and dressings, and desserts.[34][35] Their buds and greens are used in teas, and their buds, processed by bees, are the essential ingredient of amonofloral honey.[36]
Lavender was introduced into England in the 1600s. It is said that QueenElizabeth I of England prized a lavender conserve (jam) at her table, so lavender was produced as a jam at that time, as well as used in teas both medicinally and for its taste.[33]
Lavender was not used in traditional southern French cooking at the turn of the 20th century. It does not appear at all in the best-known compendium of Provençal cooking, J.-B. Reboul'sCuisinière Provençale.[38] French lambs have been allowed to graze on lavender as it is alleged to make their meat more tender and fragrant.[33] In the 1970s, a blend of herbs calledherbes de Provence was invented by spice wholesalers. Culinary lavender is added to the mixture in the North American version.[39]
In the 21st century, lavender is used in many world regions to flavor tea, vinegar,jellies, baked goods, and beverages.[40]
For most cooking applications, the dried buds (also called flowers) are used.
The potency of the lavender buds increases with drying which necessitates more sparing use to avoid a heavy, soapy aftertaste. Chefs note to reduce by two-thirds the dry amount in recipes that call for fresh lavender buds.[33][41][better source needed]
Lavender buds can amplify both sweet and savory flavors in dishes and are sometimes paired with sheep's milk and goat's milk cheeses. Lavender flowers are occasionally blended withblack,green, orherbal teas. Lavender flavors baked goods and desserts, pairing especially well with chocolate. In the United States, both lavender syrup and dried lavender buds are used to make lavenderscones andmarshmallows.[42][43]
Lavender buds are put into sugar for two weeks to allow the essential oils and fragrance to transfer; then the sugar itself is used in baking. Lavender can be used in breads where recipes call forrosemary.[citation needed] Lavender can be used decoratively in dishes or spirits, or as a decorative and aromatic in a glass of champagne. Lavender is used in savory dishes, giving stews and reduced sauces aromatic flair. It is also used to scent flans, custards, and sorbets.[33]
The flowers yield abundantnectar, from which bees make a high-qualityhoney.Monofloral honey is produced primarily around theMediterranean Sea, and is marketed worldwide as a premium product. Flowers can be candied and are sometimes used ascake decorations. It is also used to make "lavender sugar".[36]
Flower spikes are used for dried flower arrangements. The fragrant, pale purple flowers and flower buds are used inpotpourris. Lavender is also used as herbal filler inside sachets used to freshen linens. Dried and sealed in pouches, lavender flowers are placed among stored items of clothing to give a fresh fragrance and to determoths.[45] Dried lavender flowers may be used for weddingconfetti. Lavender is also used inscented waters,soaps, andsachets.
Theancient Greeks called the lavender herb νάρδος: nárdos, Latinized asnardus, after the Syrian city of Naarda (possibly the modern town ofDuhok, Iraq). It was also commonly callednard.[46] The species originally grown wasL. stoechas.[5]
DuringRoman times, flowers were sold for 100denarii perpound, which was about the same as a month's wages for a farm laborer, or fifty haircuts from the local barber. Itslate Latin name waslavandārius, fromlavanda (things to be washed), fromlavāre from the verblavo (to wash).[16][47]
^abcd"Lavender". Drugs.com. 19 December 2022. Retrieved24 June 2024.
^ab"Lavender". Drugs and Lactation Database (LactMed), National Library of Medicine, US National Institutes of Health. 3 December 2018.PMID30000925. Retrieved15 August 2019.
^Umezu, Toyoshi; Nagano, Kimiyo; Ito, Hiroyasu; Kosakai, Kiyomi; Sakaniwa, Misao; Morita, Masatoshi (1 December 2006). "Anticonflict effects of lavender oil and identification of its active constituents".Pharmacology Biochemistry and Behavior.85 (4):713–721.doi:10.1016/j.pbb.2006.10.026.PMID17173962.S2CID21779233.
^Carr, G.W; Yugovic, J.V; Robinson, K.E. (1992).Environmental Weed Invasions in Victoria – conservation and management implications. Victoria, Australia: Department of Conservation and Environment and Ecological Horticulture.
^Placzek, M; Frömel, W; Eberlein, B; Gilbertz, KP; Przybilla, B (2007)."Evaluation of phototoxic properties of fragrances".Acta Dermato-Venereologica.87 (4):312–6.doi:10.2340/00015555-0251.PMID17598033.Also, oils of lemon, lavender, lime, sandalwood, and cedar are known to elicit cutaneous phototoxic reactions, but lavender, sandalwood, and cedar oil did not induce photohaemolysis in our assay...Lavender oil and sandalwood oil did not induce photohaemolysis in our test system. However, a few reports on photosensitivity reactions due to these substances have been published, e.g. one patient with persistent light reaction and a positive photo-patch test to sandalwood oil
^Mark Griffiths,Index of Garden Plants (Portland, Oregon: Timber Press, 1994.ISBN0-333-59149-6),
^"The Forme of Cury". Project Gutenberg. Retrieved29 October 2020.PUR FAIT YPOCRAS. XX.IX. XI. Treys Unces de canett. & iii unces de gyngeuer, spykenard de Spayn le pays dun denerer, garyngale, clowes, gylofre, poeurer long, noiez mugadez, maziozame cardemonij de chescun i quart' douce grayne & de paradys stour de queynel de chescun dim unce de toutes, soit fait powdour &c.
^Laget, F. (2005). "From its Birthplace in Egypt to Marseilles, an Ancient Trade: Drugs and Spices".Diogenes.52 (3):131–139.doi:10.1177/0392192105055941.S2CID144212782.
^Charles, Denys J. (2012),"Lavender",Antioxidant Properties of Spices, Herbs and Other Sources, New York, NY: Springer New York, p. 365,ISBN9781461443100, retrieved5 September 2021
^The origin of most of these quotes comes from Dr. William Thomas Fernie, in his book "Herbal Simples" (Bristol Pub., second edition, 1897),page 298:
'By the Greeks the name Nardus is given to Lavender, from Naarda, a city of Syria near the Euphrates, and many persons call the plant "Nard." St. Mark mentions this as Spikenard, a thing of great value. In Pliny's time, blossoms of the Nardus sold for a hundred Roman denarii (or L.3 2s. 6d.) the pound. This Lavender or Nardus was called Asarum by the Romans, because it was not used in garlands or chaplets. It was formerly believed that the asp, a dangerous kind of viper, made Lavender its habitual place of abode, so that the plant had to be approached with great caution.'
^Oxford English Dictionary (second ed.). 1989.Note however that Upson and Andrews refer to research on bathing in the Roman Empire, and state that there is no mention of the use of lavender in works on this subject.
