Peganum harmala, known by several common names including Esfand, wild rue, Syrian rue, or African rue, belongs to the family Nitrariaceae.
Origins and Habitat
This plant is native to regions from the eastern Iranian area to India. It has also spread to North America, South Australia, and South Africa. P. harmala typically thrives in areas with hot summers, such as the Central and Upper Jezira Plains of Iraq, where average summer temperatures exceed 40°C.
It was initially introduced to North American at Deming, New Mexico in 1928. African rue can grow in dry conditions, even semi-desert to desert habitats. The plant is found in disturbed environments such as roadsides and fields in the desert to semi-desert areas.
Plant Characteristics
African rue is a herbaceous perennial that grows from a deep taproot.
- Mature plants are globose and can reach a height of 50 cm.
- Mature stems are often decumbent resulting in a more prostrate, spreading habit.
- Plants are bright green and can have a whitish-bluish hue.
- Leaves alternate, dark green, fleshy, and highly dissected.
- Leaves are irregularly divided into narrow, smooth lobes.
- Flowers are showy white with 5 petals, green sepals and prominent yellow stamens borne on pedicels along the upper half of the stem.
- Solitary white flowers grow on short stems (1-2 cm) from leaf axils (where the leaf meets the stem).
- Seeds are medium-size and borne in a 2-celled or 4-celled green capsule that dries and burst open at maturity.
Growing Conditions
African rue prefers a light, well-drained but moisture-retentive soil and an open position in full sun. Although this species comes from dry desert areas, it responds well to cultivation so long as the soil is very well drained. It can tolerate temperatures down to about -20°c if the soil is dry. It can grow in a variety of soils, tolerating alkaline and saline soils.
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Cultivation Tips
Seed - sow late spring in a greenhouse. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in a sunny part of the greenhouse for their first winter. Be careful not to overwater, especially when the plants are dormant. Plant out into their permanent positions in late spring or early summer.
The peganum harmala seeds germinate fairly reliably by scattering them thinly over the surface of normal, moist seed mix and tamping them in. Keep in a little bit filtered sun and maintain moisture. Temperature should be kept warm.
Once they seem like they have solid bases at the stem, carefully transplant with attention to the fine root hairs and adhering soil, so as not to unduly break them or bare-root the seedlings. Repot by burying a little deeper then before. Place out of full sun for awhile and water them but don’t overdo it.
Germination: Syrian Rue likes a well-drained not too damp and not too rich medium. The seed flat must be kept in the dark for the seeds to germinate.
Growing: Syrian Rue needs full sun and a well-drained to dry, poor soil. If you are growing it too wet, the roots will die causing the top to go limp and die because the remaining roots can’t keep up with evaporation. If you are growing the plant too rich, the growth will be too lush and soft and become very susceptible to fungus infection and bug damage.
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Traditional and Medicinal Uses
The fruit and seed are digestive, diuretic, hallucinogenic, narcotic and uterine stimulant. They are taken internally in the treatment of stomach complaints, urinary and sexual disorders, epilepsy, menstrual problems, mental and nervous illnesses. The seed has also been used as an anthelmintic in order to rid the body of tapeworms.
The seeds contain the substance ‘harmine’ which is being used in research into mental disease, encephalitis and inflammation of the brain. Small quantities stimulate the brain and are said to be therapeutic, but in excess harmine depresses the central nervous system. A crude preparation of the seed is more effective than an extract because of the presence of related indoles.
The oil obtained from the seed is said to be aphrodisiac. The oil is also said to have galactogogue, ophthalmic, soporific and vermifuge properties. The seed is used externally in the treatment of haemorrhoids and baldness.
A decoction of the leaves is used in the treatment of rheumatism. The root has been used as a parasiticide in order to kill body lice.
A red dye is obtained from the seed. It is widely used in Western Asia, especially as a colouring for carpets.
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Caution: This remedy should be used with caution and preferably under the guidance of a qualified practitioner since excessive doses cause vomiting and hallucinations.
Ecological Impact and Control
African rue is extremely drought tolerant and undergoes rapid vegetative growth when soil moisture is high, and it secretes allelopathic chemicals into the soil that reduce the growth of surrounding native plants. The young seedlings are capable of growing during periods of extreme water deficits.
This weed is extremely toxic to cattle, sheep, horses, and humans; it contains at least four poisonous alkaloids. The seeds and fruit are the most toxic, followed by young leaves and mature leaves.
African rue has a complex root system and it is extremely difficult to control the plant using only mechanical techniques.
Important Notice: DO NOT BURN. The toxicity of the plant is so high that the wood cannot be burned. The chemicals within the plant are released when burnt, causing the smoke to become toxic.
These methods easily spread new plants along transportation corridors such as railcars, and earth-moving equipment.
It is found in disturbed environments such as roadsides and fields in desert to semi-desert areas.
Since fire can release its toxic chemicals, if any wildfires were to hit an area infested with African Rue there could be severe secondary impacts.
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Chemical Composition
The ripe seed contains 3.8 - 5.8% of the alkaloids harmine, harmaline, harmalol and peganine. Ineffective as a contact poison, they are active in vapour form where they are effective against algae, in higher concentrations to water animals and lethal to moulds, bacteria and intestinal parasites.
Key Facts About African Rue
| Feature | Description |
|---|---|
| Common Names | Esfand, Wild Rue, Syrian Rue, African Rue |
| Scientific Name | Peganum harmala |
| Family | Nitrariaceae |
| Native Region | Eastern Iranian region to India |
| Habitat | Disturbed areas, roadsides, desert to semi-desert areas |
| Toxicity | Toxic to cattle, sheep, horses, and humans |
| Key Alkaloids | Harmine, Harmaline, Harmalol, Peganine |
Remember to always use ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING when dealing with potentially harmful plants.
