Guinea Hen Weed (Petiveria alliacea) is a medicinal plant widely used in folk medicine for its anti-inflammatory, analgesic, and spiritual properties, being valued in various cultures of Latin America, the Caribbean, and Africa. Native to the tropical regions of the Americas, this species stands out for its characteristic garlic aroma and its prominent presence in traditional rituals and natural healing practices.
It is native to the Amazon forest and the tropical regions of South America, Central America, and the Caribbean. It has been widely distributed from Florida, Mexico, the Antilles, through the north and coast of Argentina, to Bolivia, Colombia, Peru, and virtually all regions of Brazil, including the Amazon, Northeast, Southeast, and Midwest. The plant is not native to Africa, but was introduced there and became popular. According to Camargo (2007), Petiveria alliacea was brought to Africa in the 19th century by freed blacks returning to the African continent.
Its natural habitat includes moist and shaded areas, edges of forests, abandoned fields, and disturbed lands. It adapts well to fertile soils, rich in organic matter, and is tolerant to partial shade. This wide geographic distribution contributes to a variety of popular names: anamu, mucura, tipi, garlic weed, Guinea Hen Weed root, among many others.
The genus name Petiveria honors the English botanist James Petiver (1663–1718), notable for his contributions to botany and entomology. The specific epithet alliacea refers to the garlic-like odor (Allium), released from the leaves and roots of the plant when crushed. The botanical synonym Petiveria tetrandra is also widely recognized for the species.
Guinea Hen Weed is a perennial subshrub, sub-woody, with erect and branched growth, reaching between 20 to 100 cm (7.9 to 39.4 inches) in height. The base of the stem has a semi-woody texture, becoming more herbaceous in the upper branches, which are long, slender, and ascending. The stem is cylindrical, with an epidermis composed of irregular cells, non-glandular multicellular trichomes, and paracytic type stomatal complexes.
The roots are fusiform, irregularly branched, with coloration ranging from light grayish-brown to yellowish-brown, and have a surface with fine longitudinal striations and warty scars, giving them a rough appearance. They emit a strong, penetrating odor, similar to that of garlic, due to the presence of sulfur compounds.
The leaves are simple, alternated, stipulated, with a texture ranging from membranous to herbaceous. They measure from 2 to 4 inches (5 to 10 cm) in length and 0.8 to 2.4 inches (2 to 6 cm) in width, have an oblong-lanceolate shape, acuminate apex, and cuneiform base. The petioles are short, and the central vein is prominent on the lower (abaxial) surface, with arched secondary veins. The leaves are two-colored, being darker green on the upper (adaxial) surface.
Guinea Hen Weed displays spiciform inflorescences, which can be axillary or terminal, composed of small, white, sessile flowers arranged along a slender central axis. The flowers are dioecious, meaning male and female plants occur separately. Flowering is most common between November and March, coinciding with the rainy season in tropical regions.
The flowers are hermaphrodite (despite references to dioecious individuals, there are contradictory reports in the literature), with an androecium consisting of four stamens (hence the name tetrandra) and a unicarpelar gynoecium with a superior ovary. Pollination is entomophilous, carried out by insects attracted by the characteristic odor of the flowers and their nectaries. Fruiting occurs between April and May.
The fruit is a small, cylindrical, flattened achene with crenated edges, which easily detaches from the inflorescence after maturation. The seeds are small and hard, with a relatively high germination capacity under ideal moisture and temperature conditions.
Guinea Hen Weed is highly valued in traditional medicine across the Americas for its anti-inflammatory, analgesic, antimicrobial, and sedative effects. Its roots and leaves concentrate bioactive compounds such as sulfur compounds, flavonoids, and alkaloids, responsible for its therapeutic properties. It is one of the most utilized plants in popular phytotherapy and its use as a medicinal plant is one of the main factors supporting its cultivation in traditional gardens and yards (see the box next to it about its medicinal properties and indications).
Guinea Hen Weed carries a long history of use permeated with symbolic, religious, and social meanings. Guinea Hen Weed’s use dates back to the indigenous cultures of the Amazon and has been perpetuated through Afro-Brazilian knowledge, especially among populations descended from enslaved Africans. According to historical records, this plant was known as amansa-senhor, which means “tame sir”, a name that alludes to its supposed use by slaves to induce physical and mental debilitation in their masters through poisoning— a fact that envelops the species in mysteries, fears, and respect.
Guinea Hen Weed is also strongly associated with spiritual healing practices, protection, and smudging, being used in Umbanda, Candomblé, Catimbó, and popular blessing rituals. In these practices, it is believed to act against the “evil eye,” negative energies, and unwanted entities, being considered a plant of power that cleanses and protects both the environment and the body.
Furthermore, it is mentioned in various folkloric and literary sources as a symbol of cultural resistance and ancestry. Its leaves are used in baths, amulets, and rites of passage, which broadens its role in Brazilian and Caribbean folk culture.
Although more commonly known for its medicinal properties and rituals, Guinea Hen Weed can also be successfully used in medicinal herb gardens, healing gardens, and agroecological vegetable gardens. As a hardy plant, adaptable and easy to propagate by seeds and cuttings, it is ideal for shaded flower beds, small living fences, and borders.
Its medium stature and dense, aromatic foliage make Guinea Hen Weed interesting as a highlight plant in garden corners focused on spirituality, protection, or integration with symbolically used species. It is also an excellent choice for landscaping projects with an ethnobotanical or educational focus, valuing traditional knowledge. Its dense, branched growth, with evergreen leaves and delicate flowering, makes it not just a useful, but also an ornamental shrub.
In an urban context, it can be grown in large pots or planter boxes, provided they are well-drained and positioned in partially shaded locations. It is considered one of the important herbs in the traditional “seven-herb pot,” which serves as a spiritual protector. Its characteristic smell also acts as a natural repellent, aiding in the control of undesirable insects in the garden.
Guinea Hen Weed is a tropical plant thriving in warm and humid climates, developing more vigorously at temperatures between 68°F (20°C) and 86°F (30°C). However, it is quite rustic and can tolerate temperature variations, withstanding periods of slightly below 59°F (15°C) temperatures, provided there are no intense or repeated frosts.
Although it prefers partial shade, Guinea Hen Weed can also be cultivated in full sun, as long as the soil is kept moist. In hotter areas, partial shading helps prevent excessive water loss and drying of the leaves.
It adapts to various soil types but grows best in clayey or sandy-clay soils, rich in organic matter, well-drained, and slightly acidic to neutral (pH between 5.5 and 6.8). Light substrates with good moisture retention, such as those prepared with worm castings, topsoil, and sand, facilitate pot cultivation.
For direct planting in the ground, it is recommended to thoroughly till the soil, incorporate organic compost or humus, and choose sites with good drainage. Seedlings can be planted in holes of 8 x 8 inches (20 x 20 cm), with spacing of 20 to 32 inches (50 to 80 cm) between plants, allowing good aeration.
Pot cultivation is also possible and quite common in urban gardens and backyards. Pots with a minimum depth of 10 inches (25 cm) are ideal, always with drainage holes. The substrate can contain equal parts of topsoil, washed sand, and organic compost. Watering should be regular, keeping the soil lightly moist but never waterlogged. In dry or hot climates, increase the frequency to two or three times a week.
Fertilization can be done every two months with organic compost, alternating with balanced mineral NPK fertilizers (10-10-10), especially during vegetative growth. Staking is optional but can be useful for plants grown in intensely windy locations or with excessively long and drooping branches. The use of bamboo or wooden stakes helps in support.
Pruning should be done to remove dry leaves and branches, as well as to control excessive plant growth. Drastic pruning can stimulate vigorous sprouting and facilitate the harvesting of fresh leaves, used medicinally.
The harvesting of Guinea Hen Weed leaves should preferably be done in the morning, selecting the most developed and healthy leaves, always using a clean pair of scissors to avoid damaging the plant. Regular removal stimulates new shoots and denser branching, and it is possible to dry the leaves in the shade for later use in infusions or herbal preparations.
Guinea Hen Weed is considered a resilient plant, adapting to tropical and subtropical environments, with moderate resistance to wind and short periods of drought. However, it does not tolerate intense frosts, which can cause necrosis of the leaves and even the death of the plant in extreme cases.
During the winter in the Southern and Southeastern regions of Brazil, the plant may slow its growth rate or lose some of its foliage, sprouting again in spring. It is not suitable for coastal regions, due to its sensitivity to salt and saline winds.
Petiveria alliacea has a low incidence of pests, considered relatively resistant due to its distinctive aroma and natural antimicrobial and repellent properties. However, it may occasionally be attacked by aphids, scale insects, or mites, especially in stuffy environments with poor ventilation and lighting. Guinea Hen Weed can be propagated either by seeds or by cuttings:
- By seeds: Germination occurs between 10 and 20 days after planting, preferably in seed trays with light, moist substrate. After 20 to 30 days, the seedlings can be transplanted to a permanent location.
- By cuttings: This is the most efficient and quickest method of propagation. Healthy branches, about 6 to 8 inches (15 to 20 cm) in length, should be cut with a sterilized pair of scissors and planted directly in moist substrate.
