Datura metel 'Golden Queen' – Golden Queen Datura
Datura metel is one of the most spectacular representatives of the Datura genus in the nightshade family (Solanaceae), which also includes tomatoes, potatoes, peppers and tobacco. The species was described by Carl Linnaeus in Species Plantarum in 1753; he derived the epithet “metel” from the Arabic name jouz-mathel, under which the plant was described in the 11th century by the Persian scholar Avicenna. The genus name itself comes from the Sanskrit dhattūra, adopted into Hindi as dhatūra - a thorny plant whose fruit is still called thorn apple in English today. Other English names, devil's trumpet and horn of plenty, reflect both the flower's shape and the plant's dangerous reputation.
'Golden Queen' is a horticultural cultivar with double, golden-yellow flowers, also found in commerce under the names 'Double Golden Queen' and, incorrectly, Brugmansia 'Golden Queen'. It belongs to the group of yellow-flowered, double forms formerly distinguished as Datura metel var. chlorantha, which, alongside the purple 'Fastuosa', are the oldest known cultivars of the species. This plant is for gardeners who want to achieve a large, exotic-looking shrub with dozens of fragrant trumpets in a single season, while also accepting that they are dealing with one of the most poisonous ornamental plants.
Botanical description and plant habit
Datura metel is an annual herbaceous plant or short-lived perennial with a spreading, shrubby habit. The stems are thick, hollow, smooth or finely hairy, green or - in colored forms - purplish-black, and strongly fork-branched. The plant reaches 1–1.5 m, and under favorable conditions almost 2 m in height and a comparable width; in the 'Golden Queen' cultivar, a mature specimen typically measures about 1.2–1.4 m tall and 1.2 m wide. The entire plant releases a characteristic, heavy scent when crushed.
The leaves are simple, alternate, ovate to broadly ovate, 10–20 cm long, with entire or coarsely, irregularly toothed margins, and borne on long petioles. The flowers grow singly in the stem forks. The calyx is tubular and five-angled, while the corolla is funnel- to trumpet-shaped, 15–20 cm long; in the 'Golden Queen' cultivar, it consists of two or three layers growing out of one another, with frilled margins extended into sharp teeth. The flowers stand upright or obliquely rather than hanging as in Brugmansia. The fruit is a spherical, fleshy capsule several centimeters in diameter, covered with conical warts or short, sparse spines; it splits irregularly and releases numerous flattened, kidney-shaped seeds ranging in color from light brown to yellowish.
Origin and history of the species
The history of Datura metel is one of botany's more intriguing mysteries. For centuries, the species was considered native to India or southern China, where it grew and was cultivated since ancient times; it was described as early as by Arab and Persian authors, and in India it has been known since at least the 4th century AD. However, modern genetic and morphological research has shown that Datura metel is not a wild species, but a group of ancient cultivars selected from the Mexican thorn apple, Datura innoxia, as early as pre-Columbian times. Growers in Central America selected plants with colorful, double flowers, longer flowering periods and less spiny fruits. Plants of the World Online lists central, southeastern and southwestern Mexico as its native range, and almost the entire tropical and subtropical zone as its secondary range: from Afghanistan, India and China to Africa, Australia and the Caribbean.
In the wild, naturalized populations inhabit ruderal habitats - roadsides, wasteland, field margins and dry, sunny slopes in a seasonally dry tropical biome. The plant is light-loving, tolerates periodic drought thanks to its fleshy root and spreads prolifically from seed, so in warm regions it is sometimes treated as a weed.
Growth rate and development
Datura grows at a rate that is difficult to expect from an annual plant. A young plant planted out at the beginning of summer forms a bush 0.5 to over 1 m tall within 4-5 months, provided it has plenty of warmth, water and nutrients. Growth follows a forked branching pattern: each stem fork produces one flower and then two new shoots, causing the number of flowers to increase geometrically as summer progresses. In a temperate climate, the plant usually lives for one season; overwintered in a container, it survives for 2-3 years, although older specimens lose vigor and are usually replaced with new ones.
Flowering and propagation
Flowering begins approximately four months after young plants are planted out and lasts from July to October, until the first frosts. The flowers open in the evening and last 1-2 days; their fragrance, also perceptible during the day, becomes intense, sweet and slightly intoxicating after dark. In its natural range, the main pollinators are hawk moths, while in gardens the flowers are also eagerly visited by bees and bumblebees. In the 'Golden Queen' cultivar, the corolla is canary yellow to golden, usually uniformly colored inside and out.
The species is propagated from seed, and less commonly from stem cuttings rooted in summer. It should be remembered that double-flowered Datura metel cultivars are not completely genetically uniform: most seedlings of 'Golden Queen' produce double flowers, but plants with semi-double, single or lighter, creamy yellow flowers also occur in the population. The plant is self-pollinating and produces abundant fruit in a warm summer, allowing seeds to be harvested at home; however, ripening capsules are the most toxic part of the plant and require careful handling.
Toxicity - most important warning
All parts of Datura metel contain tropane alkaloids: scopolamine (hyoscine), hyoscyamine, atropine, as well as the species-specific meteloidine and datumetine. The highest concentrations occur in the seeds and flowers, but the leaves, stems and roots are also poisonous. Alkaloid content varies depending on the plant's age, growing site and weather, so the dose cannot be predicted - even a small amount can cause severe poisoning, with dilated pupils, dry mucous membranes, accelerated heart rate, hallucinations, convulsions and, in severe cases, death. The plant should not be grown in gardens accessible to small children or animals prone to chewing plants. When pruning and collecting seeds, it is advisable to wear gloves and avoid touching the eyes, while plant residues should not be added to compost intended for vegetable beds.
Environmental requirements and tolerance
Datura is a full-sun plant: it needs at least 6 hours of direct light, while in shade it grows weakly and flowers sparsely. The optimal growth temperature is 20–30 °C; below 10 °C, growth stops, and frost destroys the above-ground parts. PFAF rates the species' hardiness as USDA zones 8–11, although in zone 8 survival applies only to the tuberous root under a thick layer of mulch. The soil should be fertile, humus-rich but well-drained, with a neutral to slightly alkaline pH; the plant tolerates sandy and clay soils provided they are not waterlogged. Thanks to its fleshy roots, it tolerates short periods of drought well, but in hot weather its large leaves wilt after just a few hours without water and recover quickly after watering.
Cultivation in temperate climates
In cooler regions of Europe, Datura metel 'Golden Queen' is grown as an annual, planted out into its permanent position only after the risk of frost has passed. The site should be warm and sheltered from wind - the large leaves and brittle stems are easily damaged - and very sunny, for example beside a south-facing wall of a building. A spacing of 80–100 cm between plants is recommended in beds. Water generously during the growing season and fertilize regularly: every 7–14 days with a balanced fertilizer for flowering plants. The plant is a heavy feeder and grows much more poorly in poor soil.
Growing it in a container with a capacity of 15–20 l or more makes overwintering possible. In autumn, before the first frosts, shorten the stems by half or more and move the pot to a bright, cool room at 5–12 °C, reducing watering to the minimum necessary to prevent the root from drying out. In spring, the plant regrows and flowers earlier than seedlings. It is advisable to avoid planting it near tomatoes, potatoes and peppers, with which Datura shares viral diseases, and to monitor the plants for spider mites, aphids and whiteflies, especially in a dry, warm room during overwintering.
Use in ornamental gardening
The 'Golden Queen' cultivar is a classic solitary plant for an “exotic” garden: one plant fills a square metre of space during the summer, and its double, golden trumpets are visible from a distance. It combines well with cannas, castor beans, banana plants, large ornamental grasses, dark-leaved dahlias and other plants with a lush, tropical character. Because of its evening fragrance, it is planted near a terrace or path, or in large pots on a balcony, wherever summer evenings are spent. In naturalistic perennial gardens, it is sometimes used as a contrast to small-flowered plants. The only thing to remember is that it is not suitable for a family garden with small children or for public spaces.
Cultural significance and history
Few ornamental plants have such a rich and dark history. In China, Datura metel is one of the fifty fundamental herbs of traditional medicine; in India, it is sacred to Shiva and offered to him as a sacrifice; and in the traditions of the peoples of Mozambique, it was used in initiation rituals and “ordeals by God”. In 19th-century India, it became notorious as a poison used by the Thuggee sect to drug its victims. In European medicine, the alkaloids of Datura were used to treat asthma and pain, but because the difference between the therapeutic and toxic doses was too small, they were practically withdrawn from use. As an ornamental plant, the species reached European gardens in the 16th-17th centuries; double yellow and purple forms were cultivated and illustrated in herbals as early as the Baroque period.
Who this species is for
Datura metel 'Golden Queen' is a plant for gardeners seeking a fast, spectacular effect in a single season, for lovers of exotic and sensory gardens, and for people who enjoy growing large plants in pots on a terrace. It is easy to grow - the plant forgives many mistakes as long as it has sun, water and nutrients - but it requires responsibility: awareness of its toxicity, gloves when handling it, and a position out of the reach of children and animals. It is not suitable for a preschool garden, a residential green space or a home with a dog that chews leaves.
Summary
Golden Queen Datura combines huge, double, fragrant flowers in a golden colour rare among daturas with impressive growth and modest cultivation requirements. As an ancient Mexican cultivar grown in Asia for at least fifteen hundred years, it also has a fascinating history. The species is not threatened - as a cultivated plant established throughout the tropical zone, it is not listed on the IUCN Red List - and the only serious concern regarding its cultivation is its high toxicity, which must be treated with the utmost seriousness.
