English lavender (Lavandula angustifolia)
Dutch Lavender (Lavandula x intermedia)
Common names: garden lavender, common lavender, narrow-leaved lavender,
The species of the Lavandula genus are subshrubs belonging to the mint (Lamiaceae) family. Their rhizomes are wooden root systems heavily branched at the bottom. The roots can penetrate the soil reaching depths of even 3-4 m. The plant develops dense, bushy stems from its basal rosette. Older stems of the English lavender are 40-60 cm tall and 80-120 cm wide in diameter. The Dutch lavender is more robust, 80-100 cm tall and 150 cm wide in diameter. The alternate leaves are needle-shaped or narrow-lanceolate. Dutch lavender leaves are slightly larger and fluffy. English lavender blooms in late June or in July while Dutch lavender a little later. The flowers consist of pseudo-whorls forming tubular spikes. The flowers are blue-violet, those of the Dutch lavender having a more grayish hue but light blue or white specimens also exist.
Lavender is a native species to the Mediterranean region and is part of the South European spontaneous flora, reaching altitudes of over 1,700 m. Dutch Lavender grows in southern France and Spain, at altitudes up to 1000 m.
Lavender species prefer dry, calcareous soils of medium consistency. They are plants which require heat but they are also cold-resistant, being damaged by frost during very cold winters without snow. English lavender is propagated by stem cuttings or with transplanted seedlings. Dutch lavender is propagated only via stem cuttings. The ideal plantation period is during fall, from mid-September to late October. The optimal distance between the lavender rows is of 1-1.5 m and the distance between the stems is of 50 cm. Dutch lavender should have a slightly larger cultivation area. The next year after plantation, in late May or early June, the stems must be cut at a height of 8-10 cm. The procedure should be repeated the following year, this time the cutting height being at 15-18 cm. Subsequently, the stems should no longer be cut. To extract essential oil, lavender flowers are harvested when they are in full bloom, which means a relatively short period. To obtain dried flowers, cut flowers will be dried immediately. From 8-10 kg of flowers one can obtain 1 kg of dried drug.
The drug consists from English lavender flowers (flos Lavandulae) and essential oil obtained from fresh inflorescences (aetheroleum Lavandulae). In case of the Dutch lavender, the drug consists only from the essential oil. English lavender flowers contain 0.5-3% essential oil, having linalool and linalil acetate as main constituents. Dutch lavender flowers contain 0.9-5% essential oil. In addition to essential oils, lavender species also contain flavonoids, sterols, coumarins and tannins.
Lavender improves digestion, has sedative and antispasmodic effects. Infusion of dried lavender flowers can be used as an effective sedative in case of surfeit, stress, neurosis or insomnia. It has beneficial effects in case of upset stomach or intestines, accelerates the bile functions. As external treatment, it is used in lotions to treat rheumatism or neuritis. Lavender oil mixed with turpentine, juniper and rosemary oil, is beneficial in case of arthritis or rheumatic pain. Medical baths with lavender flowers have beneficial effects in case of rheumatism or gout and they are well-known tranquilizers. As an internal treatment, lavender oil dripped on sugar cubes is used to treat gastrointestinal problems by patients suffering from neurosis. The cosmetics industry uses the largest quantities of lavender essential oil.