Datura

Overview of Datura

Datura are herbaceous annuals and short-lived perennials in the tomato family (Solanaceae) with a confused taxonomy and disputed origin because of their extensive naturalization through temperate and tropical regions worldwide. Of the eight or nine species in the genus Datura, many naturally exhibit extreme variability in foliar and floral characteristics and many are very similar in appearance. Depending on the conditions a plant is growing under, the size of the plant, leaves, and flowers can range from very large to very small – which has led to many “new” species being described that are later found to be simply variations that developed in different locations due to varied environmental conditions.

The flowers of most Brugmansia are pendant trumpets.

Even one of its common names, angels’s trumpet, is confusing as that is also a common name for the closely related genus Brugmansia, a South American genus that differs from Datura by having woody stems, pendant flowers, and seed pods that need to be broken open. Other common names for the genus Datura include devil’s trumpets, moonflower, and thorn-apple, with the name jimsonweed referring to D. stramonium (a common weed in pastures, roadsides and waste places throughout much of the world including the U.S. and southern Canada) and horn-of-plenty applied to D. metel.

Datura growing wild in Southern California.

The greatest diversity of species occurs in Central America and Mexico, suggesting this as the origin of the genus, but there is ample evidence that these plants were used culturally both in the New World and in Asia as sacred plants for many millennia (at least 3,000 years). All Datura plants contain a number of alkaloids, especially in the seeds and flowers, that are toxic, narcotic and hallucinogenic. All parts are extremely toxic, and serious illness or death is possible from ingestion. They are also poisonous to cattle, horses and sheep. The cultivation of Datura is banned in some states and municipalities.

Of the nine species of Datura, only two of these herbaceous annuals/tender perennials are commonly used as ornamentals. D. inoxia, native to Central America, Mexico and the southwestern US, is the most common, along with D. metel, native to southeast Asia. The weedier D. stramonium, native to North America with smaller flowers and tooth-edged leaves, is occasionally grown as an ornamental. Even the tender perennial species are fast-growing and easily grown as seasonal annuals from seed in the Midwest.

These shrubby, sprawling warm season plants tend to grow fairly large in a single growing season. D. metel has a mounded habit and can grow 2 to 3 feet tall and at least as wide, and up to twice as wide under ideal conditions and a long growing season. D. stramonium generally grows 3 to 4 feet tall and wide but often flops under its own weight. D. inoxia has a more upright habit with a regular branching pattern and can get up to 5 feet tall. The gray-green to dark green alternate leaves up to 10 inches long and 4 inches wide have a lobed or toothed margin. Their surfaces are either smooth (D. metel in most cases and D. stramonium) or downy (D. inoxia). The coarse-textured foliage is foul smelling when handled and the sap can cause skin irritation sensitive individuals.

Datura plants are shrubby and spreading (L) with leaves that vary in color from medium green to gray-green and with entire to lobed or toothed margins (C and R).

The large, erect, trumpet-shaped flowers range in color from pure white to pinkish purple, but some species have flowers that are bright golden yellow or red-purple, and some have double or triple blooms. The petals are fused to form a funnel with 5 or 10 lobes. The furled, cigar-shaped flower buds unwind after dusk (vespertine) and the flowers remain open until about noon of the following day when the petals begin to decline. The flowers exude a pleasant honeysuckle-like scent, especially at night, which attracts night-flying sphinx moths which are their primary pollinators. The flowers may also be visited by honey bees and other insects. Plants bloom continuously from summer until frost.

Erect cigar-shaped flower buds (L) open at the tip (LC) to unfurl (C) to an erect trumpet-shaped bloom (RC). Flowers range in color from pure white to pinkish purple (RC).

Flowers are followed by rounded fruits that are walnut-sized capsules that are knobby (D. metel) or covered with sharp and spiky spines at maturity (D. inoxia and D. stramonium). The capsules split open when ripe to release the numerous flattened tan or brown seeds that are similar in appearance to stout tomato seeds. Unless the seed capsules are removed before maturity, the plants tend to self-seed and reseeding can be aggressive. Seeds remain viable for years.

Fruits are rounded capsules (L and LC) that split open when ripe (C) to release the numerous seeds (RC and R).

Landscape Use of Datura

The large, coarse foliage of datura contrasts well with many other plants with fine or medium texture.

The large white flowers are ideal for moon gardens.

Datura tends to be large, sprawling plants with a coarse texture, so they are best suited as specimen or background plants in mixed or annual plantings. Plant them where the fragrance of the dramatic flowers may be enjoyed. The bold foliage contrasts well with short ornamental grasses (such as shorter annual or perennial Pennisetum or ruby grass) and annuals with fine or medium foliage and lots of flowers, such as Profusion series zinnia or petunia.

Grow datura in full sun and well-drained soil (it will grow in partial shade, but will be leggier and have fewer flowers). It is drought tolerant once established and thrives in almost any type of soil, but the plants prefer moist soil conditions.

Datura grows quickly and needs plenty of room.

Datura needs plenty of room and quickly grows to fill an area of several feet once the weather gets hot, so site them accordingly.

Propagating Datura

Datura may be grown from seed sown outdoors after the last frost or started indoors 6 to 8 weeks before the average date of last frost and planted outdoors after all threat of frost has passed (and after acclimating the young plants to outdoor conditions).

Datura grows quickly from seed, often in dense groups when self-sown (L), producing narrow cotyledons (LC) and then rounded leaves (RC and R).

Although they can be grown in large containers, Datura is best grown in the ground because of their size. Plants can be cut back if necessary to shape the plants. Staking may be necessary for some plants. Datura has few pest problems, but may be attacked by whiteflies, mealybugs, or spider mites.

Cultivars of Datura

There are several cultivars and hybrids of datura available. Often the species is not listed when offered for sale, and sometimes the same variety is listed under different names, including species names that are not scientifically accepted. Varieties include:

D. inoxia ‘Missouri Marble’ has grey-green leaves with irregular cream variegation, purple stems, and single white flowers with violet-purple mottling.
D. metel ‘Aurea’ has yellow flowers.
D. metel ‘Ballerina’ series is compact, growing 3 feet tall and wide with ruffled, tutu-like flowers. It is available in ‘Purple’, ‘Yellow’, ‘White’, and a mixture of these colors.
D. metel ‘Black Currant Swirl’ (sometimes listed as ‘Double Purple’ or ‘Purple Hindu’) is a hybrid or variety of D. metel with bicolor, double flowers that are dark purple on the outside and white inside. Flowers remain open during the day and are not very fragrant.
D. metel ‘Flore Pleno’ has white, double flowers.
D. hybrida ‘Golden Queen’ is a hybrid variety with yellow, single flowers. A double flowered yellow variety is sometimes offered under this name.