Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
What are Datura?
Datura (Datura spp.) is a genus of herbaceous plants that is a member of the Solanaceous family which includes tomatoes, peppers, eggplant and potatoes. The genus includes 9 species. Although some of the species appear to have originated in other countries, the genus is thought to be native to Central Mexico. After the Spanish colonization of Mexico, the plants spread all over the world.
The plants are closely related to Brugmansia. Key differences between the two are the flowers and the growth habit. Brugmansia's trumpet flowers dangle like pendants from the stems whereas Datura's trumpet flowers face upwards. Brugmansia is a small tree with a woody stem. Datura are herbaceous plants, growing only 3 – 5 feet tall, depending on the species.
D. metel,which is often said to be from China, is the species most often grown as an ornamental. D. stramonium is found throughout the desert Southwest. It is the infamous jimson weed, known for its hallucinogenic properties. It is used by both recreational drug users and indigenous peoples. It is hardy in zones 6 – 9.
Are Datura Poisonous?
Like its brugmansia cousin, all parts of the Datura plant are poisonous. The plant contains anticholinergics which block the neurotransmitter acetylcholine resulting in hallucinations, hyperthermia, tachycardia, muscle stiffness, temporary paralysis and amnesia. Physostigmine can be administered to reverse the effects, but some victims are left with permanent damage to their heart, kidneys, lungs or stomachs. Datura is also poisonous for horses, cattle and sheep. No wonder its nickname is the Devil’s Trumpet.
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How to Grow Datura
The popular species D. metel is hardy in zones 9 – 11. In zone 8, the plant will be killed by frost, but the roots may survive the winter and regrow in the spring. The plants need full sun. They can grow in just about any soil but do best in rich, loamy, well-drained soil. Once established, the plants are drought tolerant and do not require supplemental watering unless you are experiencing a period of drought. Space your plants 3 feet apart. Be prepared to stake them. They will start to sprawl. You can also prevent sprawl by careful pruning. If you do not deadhead the flowers, be aware that the plants will self-seed in your garden. The seed can remain viable in the soil for years.
The plants grow 3 – 4 feet tall and 4 feet wide. The flowers are quite large, 7 inches long and 4 inches wide, and very fragrant, smelling like honeysuckle. They can be white, yellow, lilac or dark purple. The white flowered plants are perfect for moon gardens, resulting in another nickname, moonflower. All Datura flowers open during the night and live only until noon the following day. They open at night because they are pollinated by sphinx moths which are active at night. Remove the spent flowers when they close. Bloom time is mid-summer until frost.
If you do not remove the spent flowers, the plants will develop spiny seedpods that are approximately the size of walnuts. They are filled with tan seeds. To prevent the pods from releasing their seeds, it is recommended that you remove them before they open and discard them with your garbage. Do not throw them into your compost.
How to Grow Datura From Seed
You can direct sow Datura seeds in your garden after the last frost when the soil has reached a temperature of 60⁰F - 65⁰F. Barely cover them with soil, about 1/8 inch deep. Germination should occur in 3 – 6 weeks.
You can also start your seeds indoors 6 – 8 weeks before your last frost. Sow the seeds 1/8 inch deep in containers filled with pre-moistened soil. Rather than watering them with a regular watering can which can wash away the shallow soil covering the seeds, mist the soil instead or place your containers in a shallow tray and fill the tray with water which will then be absorbed by the soil in the containers through drainage holes. Do this until your seeds germinate at which point you can start watering with a watering can.
Germination should occur in 3 – 6 weeks. You can transplant your seedlings outdoors after your last frost. Space them 3 feet apart.
© 2020 Caren White