Overview
Valeriana officinalis — commonly known as valerian, common valerian, or garden valerian — is a hardy perennial herb native to Europe and parts of Asia, and widely naturalised elsewhere. It is most recognisable in summer when it sends up tall stems of delicate, sweetly-scented pink and white flower clusters. Its roots, however, tell a very different olfactory story: they are famously pungent, with an earthy, somewhat unpleasant smell that has been compared to dirty socks. This contrast between the attractive flowers and malodorous root is one of valerian's most memorable characteristics.
Taxonomy and Classification
| Rank | Classification |
|---|---|
| Kingdom | Plantae |
| Order | Dipsacales |
| Family | Caprifoliaceae (formerly Valerianaceae) |
| Genus | Valeriana |
| Species | V. officinalis L. |
The genus Valeriana contains over 250 species, found across temperate and tropical regions. V. officinalis is the species with the most significant history of medicinal use and the most commercially cultivated for herbal preparations.
Botanical Description
Valerian is a robust, clump-forming perennial that can reach heights of 1–1.5 metres in good conditions. Key identifying features include:
- Leaves: Pinnately compound (divided into pairs of lance-shaped leaflets), arranged oppositely on the stem. Basal leaves are long-stalked; stem leaves become progressively stalkless upward.
- Stems: Hollow, ribbed, and slightly hairy, particularly toward the base.
- Flowers: Produced from June to August in dense, flattened clusters (corymbs) at the stem tips. Individual flowers are tiny, funnel-shaped, and pale pink to white, with a sweet, pleasant fragrance.
- Root: A short, thick rhizome with numerous fibrous roots. Fresh roots are greyish-white; dried roots turn brown and develop their characteristic strong odour.
- Fruit: Small achene with a feathery pappus to aid wind dispersal.
Habitat and Distribution
Valerian is highly adaptable. In the wild, it favours:
- Damp meadows and river banks
- Woodland edges and scrub
- Roadsides and disturbed ground
- Chalk grasslands and limestone pavements
It is native across Europe from Scandinavia to the Mediterranean and east into Siberia. It has been introduced to North America, where it now grows wild in many northern regions. It typically grows at low to mid altitudes and is tolerant of a range of soil types, though it prefers moisture-retentive ground.
History and Ethnobotany
Valerian has one of the longest documented histories of any medicinal plant in European tradition. It was described by the ancient Greek physician Dioscorides in the 1st century CE, who called it phu — a name thought to reference its smell. It was listed in the pharmacopoeias of many European nations from the medieval period onward, used for conditions ranging from epilepsy and hysteria to insomnia and nervous complaints.
During the Second World War, valerian root preparations were reportedly used to treat anxiety and shell shock in some European countries, reflecting its long association with nervous system support.
The word "valerian" is thought to derive either from the Roman province of Valeria or from the Latin valere — "to be strong" or "to be well."
Active Compounds
The pharmacology of valerian is complex and not fully resolved. Key compound classes include:
- Valerenic acid and its derivatives: Sesquiterpene acids unique to V. officinalis, believed to interact with GABA receptors in the brain — the same receptors targeted by benzodiazepine drugs.
- Isovaleric acid: Responsible for much of the root's unpleasant odour.
- Iridoid compounds (valepotriates): Present in fresh root but unstable; largely degraded during drying and storage.
- Lignans and flavonoids: May contribute to overall effects.
Cultivation Notes
Valerian is an undemanding garden plant. It tolerates most soils, prefers a sunny to partly shaded position, and grows well near water features. It self-seeds readily, so deadheading after flowering will prevent it spreading. Cats are famously attracted to the plant — the roots contain compounds similar to the active principles in catnip.
Conservation Status
Valeriana officinalis is not threatened and is considered a common species throughout most of its native range. Several related species in other parts of the world, however, face pressure from over-harvesting and habitat loss.