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Albizia / Silk Tree (Albizia julibrissin)
Materia Medica
Family: Fabaceae
Accepted name: Albizia julibrissin Durazz.
Common names: Silk Tree, Persian Silk Tree, Mimosa Tree, Pink Silk Tree
Chinese bark name: Hé Huān Pí / He Huan Pi (合欢皮)
Chinese flower name: Hé Huān Huā / He Huan Hua (合欢花)
Parts used: Dried bark and dried flower heads or flower buds; these are separate materia-medica drugs
Growth habit: Deciduous shrub or small to medium tree
Native range: Eastern Transcaucasus through northern Iran and the Himalaya to China, Korea, and Japan
Primary tradition: Traditional Chinese medicine
Actions & Energetics
He Huan Pi — bark: The 2025 Chinese Pharmacopoeia describes the bark as sweet and neutral, entering the Heart, Liver, and Lung channels. Its traditional actions are to relieve constraint and calm the spirit, activate blood, and reduce swelling.
He Huan Hua — flowers: Chinese pharmacopoeial sources describe the flowers as sweet and neutral, entering the Heart and Liver channels, with the traditional action of relieving constraint and calming the spirit.
- Bark tradition: Restlessness, depressed mood, insomnia, traumatic pain, swelling, and certain abscess patterns in traditional Chinese medicine
- Flower tradition: Restlessness, depressed mood, emotional constraint, and insomnia
- Modern research: Antidepressant-like, anxiolytic-like, sedative, serotonergic, immune, and cell-signaling effects are mainly preclinical
- Important distinction: Bark and flower are not interchangeable materials and have different official dose ranges and chemical profiles
Botanical Description
Albizia julibrissin is a deciduous tree or large shrub with a broad, spreading crown. The leaves are bipinnate, giving the foliage a fern-like appearance. Each pinna bears many small oblong leaflets.
The showy flower heads are usually pink, with numerous long staminal filaments creating the characteristic silky “powder-puff” appearance. The corollas themselves are small compared with the stamens. After flowering, the tree produces flat, papery, bean-like pods containing several flattened seeds.
Name Confusion & Look-Alikes
“Mimosa” is an ambiguous common name. In the United States, Albizia julibrissin is commonly called mimosa tree, but true Mimosa species belong to a different genus. Herbal and medicinal material should therefore identify Albizia julibrissin by botanical name rather than relying on “mimosa” alone.
The older spelling Albizzia julibrissin appears frequently in pharmacology papers. It refers to the same species but is not the currently accepted spelling.
He Huan Pi means the bark, while He Huan Hua means the flower head or flower bud material. These two official drugs should not be treated as a single interchangeable herb.
Traditional Indications
Traditional Chinese medicine uses He Huan Pi for emotional constraint, restlessness, insomnia, traumatic pain, swelling, and related pattern-based indications. He Huan Hua is used more specifically for emotional constraint, restlessness, and insomnia.
These are traditional materia-medica indications. They do not establish that Albizia bark or flower alone is a proven treatment for major depressive disorder, generalized anxiety disorder, post-traumatic stress disorder, or chronic insomnia.
Preparations & Dosage
He Huan Pi — Bark Decoction
The 2025 Chinese Pharmacopoeia lists 6–12 g of dried Albizia bark for internal use. It also permits an appropriate amount externally as powdered material mixed for topical application.
He Huan Hua — Flowers
The 2025 Chinese Pharmacopoeia lists 5–10 g of dried Albizia flower heads or flower buds. This applies specifically to authenticated Albizia julibrissin flower material.
Extracts
Modern experimental studies use solvent fractions, isolated saponins, lignans, or flavonoids at concentrations specific to the laboratory protocol. Those amounts cannot be converted directly into a household bark or flower dose.
Children & Adolescents
No established modern single-herb pediatric dose has been demonstrated for Albizia bark or flower. Traditional formula use under qualified supervision is different from creating an unsupervised pediatric single-herb dose.
Modern Human Study Doses
No well-established modern single-ingredient human dose for depression, anxiety, or insomnia has been validated in controlled clinical trials. Human reports involving traditional formulas cannot be used to assign the entire effect to Albizia alone.
Classical Formulations
He Huan Pi and He Huan Hua appear in traditional Chinese compound prescriptions, but no single formula defines the full modern clinical use of Albizia. Formula selection depends on the traditional pattern, companion herbs, and whether bark or flower is being used.
For safety and accuracy, the exact formula should be checked rather than substituting one Albizia part for another or assuming that a single-herb dose equals the dose used within a multi-herb prescription.
Constituents
He Huan Pi / bark is especially notable for triterpenoid saponins known as julibrosides, together with lignans, phenolic glycosides, triterpenes, and other constituents. The 2025 Chinese Pharmacopoeia uses a syringaresinol glycoside as a quantitative quality-control marker for the bark.
He Huan Hua / flowers contain flavonoids and flavonol glycosides including quercitrin and isoquercitrin, along with aromatic constituents and other phenolics. Bark and flowers therefore should not be treated as chemically identical preparations.
Modern Research
Antidepressant-Like Research
Animal studies have reported antidepressant-like effects from A. julibrissin fractions and isolated constituents. In one mouse study, a methylene-chloride fraction produced antidepressant-like behavior at experimental doses, with findings implicating the 5-HT1A receptor system.
These are animal data and do not establish a human antidepressant dose.
Serotonin-Transporter Research
Modern biochemical work has isolated Albizia-derived lignan glycosides that noncompetitively inhibit the serotonin transporter (SERT) in laboratory systems. More recent work on the related parent compound (-)-syringaresinol also demonstrated SERT inhibition and antidepressant-like effects in animal models.
This is mechanistic research. It does not mean Albizia behaves as a standardized prescription SSRI in people.
Anxiolytic Research
Julibroside C1, an Albizia saponin, produced anxiolytic-like effects in mouse behavioral models. Other extracts have also been studied for stress- and anxiety-related pathways.
These findings remain preclinical and do not establish treatment efficacy for human anxiety disorders.
Sedative & Sleep Research
Two flavonol glycosides isolated from the flowers, quercitrin and isoquercitrin, increased pentobarbital-induced sleep time in mice in a dose-dependent manner. This provides a plausible preclinical basis for the traditional calming use of the flowers.
It does not establish a validated human sleep dose.
Immune, Cytotoxic & Other Research
Julibrosides and other Albizia constituents have shown immune-modulating, cytotoxic, antioxidant, anti-inflammatory, and cell-signaling effects in laboratory and animal studies.
These findings are early-stage natural-product research and do not establish Albizia as a cancer treatment or proven immune therapy.
Human Evidence
Direct high-quality human evidence for single-ingredient Albizia julibrissin remains limited. A 2023 review found a substantial preclinical literature and discussed clinical use of Albizia-containing formulas, but fundamental questions about mechanism, efficacy, and translation to standardized single-herb therapy remain unresolved.
Adverse Effects
Modern human adverse-effect data for single-ingredient bark or flower are limited. Traditional use and pharmacopoeial listing do not establish safety at unlimited doses or with concentrated extracts.
Because Albizia contains central-nervous-system-active constituents, concentrated preparations may cause unwanted sedation or other effects in susceptible individuals.
Interactions & Contraindications
Controlled human interaction studies are lacking. Laboratory SERT effects and animal serotonergic findings support a precautionary concern with serotonergic medicines such as antidepressants, although the magnitude of any real-world interaction has not been established.
Likewise, the traditional calming use and animal sedative findings support caution when concentrated Albizia preparations are combined with alcohol, benzodiazepines, sedating antihistamines, sleep medicines, or other central-nervous-system depressants.
Allergic reactions are also possible. Albizia belongs to the Fabaceae and produces abundant flowers and pollen.
Pregnancy & Breastfeeding
Reliable modern reproductive-safety data are insufficient for concentrated medicinal use. Traditional bark actions include activating blood and reducing swelling, which makes self-directed medicinal use during pregnancy inappropriate without qualified professional supervision.
Safety during breastfeeding is also inadequately characterized. No evidence-based lactation dose has been established for bark, flowers, or concentrated extracts.
Habitat & Cultivation
- Native range: Eastern Transcaucasus through northern Iran and the Himalaya to China, Korea, and Japan
- Growth habit: Deciduous shrub or tree with a broad spreading crown
- Leaves: Bipinnate with many small oblong leaflets
- Flowers: Pink flower heads dominated visually by long silky stamens
- Fruit: Flat papery pods with multiple seeds
- Light: Full sun to light shade
- Climate: Temperate to warm-temperate regions
The species has naturalized widely outside its native range, including many parts of the United States.
Propagation
Albizia is readily propagated from seed. Scarification or soaking is often used to improve germination of the hard-coated seeds. Young trees grow quickly in warm, sunny conditions.
Because the species spreads readily by seed and is invasive in some regions, local invasive-plant guidance should be checked before planting or distributing seedlings.
Harvesting & Drying
He Huan Pi is the dried bark of Albizia julibrissin. The 2025 Chinese Pharmacopoeia describes bark harvested in summer and autumn, cleaned and dried, then processed into strips or pieces for prepared medicinal slices.
He Huan Hua consists of dried flower heads or flower buds harvested in summer when flowers open or buds form, then promptly dried.
Because bark harvest can injure a tree, cultivated or responsibly managed sources are preferable to destructive stripping of wild trees.
Food Use
Albizia julibrissin is primarily documented as an ornamental and medicinal tree rather than a routine food plant. The medicinal bark and flowers should not be presented as ordinary culinary ingredients.
History, Folklore & Spiritual Use
The Chinese name He Huan is traditionally associated with ideas of harmony, joy, and relief from emotional constraint. Both the bark and flowers developed reputations in Chinese materia medica for calming the spirit and easing emotional distress.
The tree later became widely planted as an ornamental because of its fern-like foliage and showy pink silky flower heads. Outside its native range, that horticultural popularity also contributed to naturalization and invasive spread.
Materia Medica Summary
Albizia / Silk Tree (Albizia julibrissin) is a Fabaceae tree native from eastern Transcaucasia and northern Iran across the Himalaya to East Asia. Traditional Chinese medicine uses two distinct medicinal materials: He Huan Pi, the bark, and He Huan Hua, the flowers.
The 2025 Chinese Pharmacopoeia lists 6–12 g for He Huan Pi and 5–10 g for He Huan Hua. Modern research supports biologically plausible antidepressant-like, anxiolytic-like, sedative, serotonergic, and immune-related effects, but most evidence remains laboratory or animal based. Single-herb human efficacy and modern interaction data remain limited, and bark and flower preparations should not be treated as interchangeable.