Albizia julibrissin (silk tree)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Plant Type
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Biology and Ecology
- Latitude/Altitude Ranges
- Air Temperature
- Rainfall Regime
- Soil Tolerances
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Impact Summary
- Environmental Impact
- Impact: Biodiversity
- Threatened Species
- Risk and Impact Factors
- Uses List
- Wood Products
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Albizia julibrissin Durazz.
Preferred Common Name
- silk tree
- Albizia julibrissin var. mollis (Wall.) Benth.
- Albizia julibrissin var. rosea (Carrière) Mouillefert
Other Scientific Names
- Albizia rosea Carrière
- Albizzia julibrissin nom. illeg.
International Common Names
- English: mimosa; nemu; Persian acacia; pink siris; silktree albizia; silktree mimosa; silky acacia
- French: acacia rose de Constantinople; acacie de Constantinople; arbre a soie; arbre à soie
Local Common Names
- China: ho huan; ho hun
- Germany: Julibrissin- Albizzie; Persische Seidenakazie
- India: barau; baraulia; bhokra; bhondir; brind; buna; karmaru; kurmru; kurmura; lal; mathirshi; shirin; shirish; shishi; sirin; siris; sirsang; surangru; tandai
- Italy: acacia di Constantinopoli; albero de la seta; albizzia; gaggia arborea; gaggia di Constaninopoli
- Japan: nemu-no-ki
- Netherlands: acacia van Constantinopel
- South Africa: Julibrissin- Albizzie; persische Seidenakazie
- ALBJU (Albizia julibrissin)
Summary of InvasivenessTop of page Binggeli (1999) classifies A. julibrissin as moderately invasive. The ability of this species to grow very rapidly (sprouts can grow over 1 m in a season), resprout after damage and seed prolifically contribute to its invasiveness in favourable conditions. A. julibrissin is a weed mainly in the USA where it is being monitored in 13 southern states according to USFS policy. It is a category A weed (severe threat) in Tennessee, USA where it grows along many roadside slopes, disturbed areas and stream banks. It is also regarded as one of the top ten invasive plant species in Georgia, is a category 1 (altering plant community) species on the Florida Invasives list (SE-EPPC, 2002) and is listed as moderately invasive (with minor influence on ecosystem function and plant composition) in Virginia (Virginia Department of Conservation and Recreation, 2003). In South Africa it is proposed as a category 3 weed under the Conservation of Agricultural Resources Act 1983, subject to further investigation (Henderson, 2001).
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Fabales
- Family: Fabaceae
- Subfamily: Mimosoideae
- Genus: Albizia
- Species: Albizia julibrissin
Notes on Taxonomy and NomenclatureTop of page A. julibrissin was introduced into Europe (particularly to Florence, Italy) in 1745 from Constantinople (Istanbul, Turkey) by Filippo Degli Albizzi. This new species was described and studied first by Antonio Durazzini, who dedicated the name of the genus to Albizzi (sometimes this name is written with one 'z'). The species name 'julibrissin' derives from the corresponding Persian name. The common name 'mimosa' (a name used for the tree in southern USA) is also used for another plant, Acacia dealbata, in Italy and Texas (USA).
DescriptionTop of page A. julibrissin is a deciduous, fast-growing tree (sprouts can grow more than 1 m in a vegetative season) from 6 to 12 m high. It has a straight stem (but in nature trees can grow with multiple trunks) and a wide, spreading crown. The bark is smooth and grey-green, greener in young trees, and has angular and glabrous branches, with many lenticels. Leaves are bipinnate, with 6-12 pairs of leaflets, each divided into 20-30 pairs of ultimate segments, 1 cm long, light green and oblong. The entire leaf is about 20-30 cm long. Flowers are light pink, in terminal clusters of dense heads, each terminating in a stalk. The stamens are numerous and very long, jutting out from the corolla. The fruit is a brown, flat pod, 15 cm long, constricted between the seeds, which remains on the plant until the next spring. Seeds have an impermeable coat and can remain dormant for years. The tree flowers in June-August and fruits ripen in September-November.
Plant TypeTop of page Broadleaved
DistributionTop of page A. julibrissin is the only species of the genus that belongs to the northern hemisphere. Its natural distribution ranges from the Caucasus and Iran to Asia Minor, central China and Japan. In its native range, A. julibrissin grows in scrub and woodland on moist sites (Weber, 2003).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Planted||Reference||Notes|
|Afghanistan||Present||Introduced||Planted, Natural||ILDIS, 2002|
|Bhutan||Present||Native||Planted, Natural||ILDIS, 2002|
|China||Present||Native||Planted, Natural||ILDIS, 2002|
|Georgia (Republic of)||Present||Native||Planted, Natural|
|India||Present||Native||Planted, Natural||ILDIS, 2002|
|Iran||Present||Native||Planted, Natural||ILDIS, 2002|
|Japan||Present||Native||Planted, Natural||ILDIS, 2002|
|Korea, DPR||Present||Native||Planted, Natural|
|Korea, Republic of||Present||Native||Planted, Natural|
|Myanmar||Present||Native||Planted, Natural||ILDIS, 2002|
|Nepal||Present||Native||Planted, Natural||ILDIS, 2002|
|Pakistan||Present||Native||Planted, Natural||ILDIS, 2002|
|Sri Lanka||Present||Native||Planted, Natural|
|United Arab Emirates||Present||Introduced||Planted|
|South Africa||Present||Introduced||Planted||Henderson, 2001|
|-California||Present||Introduced||SE-EPPC, 2002; USDA-NRCS, 2002|
|-Florida||Present||Introduced||Invasive||SE-EPPC, 2002; USDA-NRCS, 2002|
|-Kentucky||Present||Introduced||Invasive||SE-EPPC, 2002; USDA-NRCS, 2002|
|-Louisiana||Present||Introduced||Invasive||SE-EPPC, 2002; USDA-NRCS, 2002|
|-New Mexico||Present||Introduced||Planted||USDA-NRCS, 2002|
|-New York||Present||Introduced||Planted||USDA-NRCS, 2002|
|-North Carolina||Present||Introduced||Planted||USDA-NRCS, 2002|
|-South Carolina||Present||Introduced||Planted||USDA-NRCS, 2002|
|-Tennessee||Present||Introduced||Invasive||SE-EPPC, 2002; USDA-NRCS, 2002|
|-Virginia||Present||Introduced||Invasive||SE-EPPC, 2002; USDA-NRCS, 2002|
|-West Virginia||Present||Introduced||Planted||USDA-NRCS, 2002|
Central America and Caribbean
|New Zealand||Present||Introduced||Planted||ILDIS, 2002|
History of Introduction and SpreadTop of page A. julibrissin was introduced into Europe (particularly in Florence, Italy) in 1745 from Constantinople (Istanbul, Turkey) by Filippo Degli Albizzi. In the same year it was introduced into the USA where it is now common in many states (USDA-NRCS, 2002). It is a beautiful ornamental tree, with sweet-smelling flowers, widely cultivated in the Mediterranean region, England, southern USA, Argentina and in some cases naturalized. In Italy it is cultivated in every region and grows wild near towns in Veneto and Lombardy. ILDIS (2002) provides information on the global distribution. A. julibrissin is widely introduced outside its native range because of its value as a shade and roadside tree, for ornament and for prevention of soil erosion, and intentional planting therefore constitutes one of the major sources of potential spread. The widespread planting of this species as an ornamental in the USA has facilitated invasion because new plants often develop from the seed of nearby established plants. SE-EPPC (2002) reports that it is sometimes accidentally spread by moving soil containing seeds.
Risk of IntroductionTop of page A. julibrissin is widely introduced outside its native range because of its value as a shade and roadside tree, for ornament and for prevention of soil erosion and intentional planting therefore constitutes one of the major sources of potential spread.
HabitatTop of page In its native range A. julibrissin grows in scrub and woodland on moist sites (Weber, 2003).
Habitat ListTop of page
|Terrestrial – Managed||Managed forests, plantations and orchards||Present, no further details||Harmful (pest or invasive)|
|Disturbed areas||Present, no further details||Harmful (pest or invasive)|
|Rail / roadsides||Present, no further details||Harmful (pest or invasive)|
|Urban / peri-urban areas||Present, no further details||Harmful (pest or invasive)|
|Terrestrial ‑ Natural / Semi-natural||Natural forests||Present, no further details||Harmful (pest or invasive)|
|Riverbanks||Present, no further details||Harmful (pest or invasive)|
Biology and EcologyTop of page Genetics
Among the cultivars are A. julibrissin 'Ernest Wilson', an extraordinarily winter-hardy plant with pink and white flowers, which originated in 1918 in the Arnold Arboretum, USA, from seeds collected by Ernest Wilson in Seoul, South Korea. A winter-hardy variety of the silk tree, A. julibrissin var. rosea, which is dwarf and bushy, with bright, strong pink flowers, has been introduced from South Korea to northern countries. Another variety, A. julibrissin var. mollis, with broader and densely pubescent leaflets, grows in the Himalayas and Ethiopia.
Physiology and Phenology
The tree flowers in June-August and fruits ripen in September-November. Longevity is about 100 years.
Seed production is prolific. The fruit is a brown, flat pod, 15 cm long, constricted between the seeds, which remains on the plant until the following spring. Seeds have an impermeable coat and can remain dormant for many years. Propagation is usually by seed (soaking and scarification may be necessary) or planting stock, while vegetative propagation is achieved using tissue culture, cuttings (including root cuttings) or suckers.
It is an easy tree to prune and reacts to pruning by producing new shoots on the stem and branches. When killed, for example by a severe winter, plants can resprout from the base. It can also be fan trained for growing on a wall. SE-EPPC (2002) states that A. julibrissin demonstrates a high level of seed viability, as long as 50 years after seed harvest.
A. julibrissin is tolerant of low temperature but young plants are frost tender and require glasshouse protection during their first year. When dormant, trees are resistant to about -20°C but this is reduced to -10°C in the maritime climate. In Florence, Italy in 1985, the temperature reached -23°C and trees survived. When killed, for example by a severe winter, plants can resprout from the base. Longevity is about 100 years. Preferred mean annual rainfall is normally in excess of 1000 mm, and up to 2300 mm, but there are records for it surviving where annual rainfall is as low as 100 mm, though probably with a permanent ground water supply.
A. julibrissin is a light-demanding species that is indifferent to soil type. Although it prefers fertile, well drained soils with clay, it is able to grow in gravelly or poor soils. It can tolerate high pH, saline soils, wind and drought. Full sun positions and southern exposures are preferred. In Europe, A. julibrissin does not grow above 900 m, although it can reach 2100 m in the Himalayas (PFAF, 1999).
It has a symbiotic relationship with certain nitrogen-fixing bacteria contained in nodules on the roots; some of this nitrogen can be used by other plants growing near A. julibrissin. Where it forms dense stands, light and nutrient levels are reduced preventing the establishment of native plants thus changing botanical composition (Weber, 2003).
Latitude/Altitude RangesTop of page
|Latitude North (°N)||Latitude South (°S)||Altitude Lower (m)||Altitude Upper (m)|
Air TemperatureTop of page
|Parameter||Lower limit||Upper limit|
|Absolute minimum temperature (ºC)||-23|
|Mean annual temperature (ºC)||9||28|
|Mean maximum temperature of hottest month (ºC)||19||45|
|Mean minimum temperature of coldest month (ºC)||-9||15|
RainfallTop of page
|Parameter||Lower limit||Upper limit||Description|
|Dry season duration||0||4||number of consecutive months with <40 mm rainfall|
|Mean annual rainfall||100||2300||mm; lower/upper limits|
Rainfall RegimeTop of page Bimodal
Soil TolerancesTop of page
Special soil tolerances
Notes on Natural EnemiesTop of page Mimosa wilt, caused by the fungus Fusarium oxysporum f.sp. perniciosum, attacks A. julibrissin through the root system and may kill it. Resistant cultivars are 'Charlotte' and 'Tryon'. Other wilt diseases include those caused by fungi of the genus Phomopsis, Nectria or Verticillium. The tree is also attacked by Flammulina velutipes, cause of stem rot. The leaves can be attacked by fungi such as Septoria curvata, which causes brown spots on the leaves and leaf fall, and by insects including aphids, cochineals and Coleoptera such as Cossus cossus or Zeuzera pyrina, which dig tunnels in branches and stems causing desiccation and breaking off. A. julibrissin is resistant to honey fungus (Armillaria sp.).
Means of Movement and DispersalTop of page A. julibrissin seeds are easily transported by water, where the tree grows near riverbanks. Seeds may also be accidentally spread by moving soil (SE-EPPC, 2002). The widespread planting of this species as an ornamental tree in the USA has facilitated invasion, as new plants often develop from the seed of nearby established plants.
Impact SummaryTop of page
|Fisheries / aquaculture||None|
Environmental ImpactTop of page Where A. julibrissin forms dense stands, light and nutrient levels are reduced preventing the establishment of other plants (Weber, 2003).
Impact: BiodiversityTop of page A. julibrissin changes botanical composition by preventing or restricting the establishment of native plants (Weber, 2003).
Threatened SpeciesTop of page
Risk and Impact FactorsTop of page Invasiveness
- Proved invasive outside its native range
- Highly adaptable to different environments
- Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
- Highly mobile locally
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Damaged ecosystem services
- Ecosystem change/ habitat alteration
- Reduced native biodiversity
- Highly likely to be transported internationally deliberately
- Difficult to identify/detect in the field
- Difficult/costly to control
UsesTop of page A. julibrissin is a beautiful ornamental species that can be used as a shade and roadside tree due to its resistance to air pollution. It can prevent soil erosion due to its large root system and the wide, flat crown. It can be cultivated to create interesting, if problematic and short-living, bonsai. It is now considered a useful agroforestry tree in silvoarable systems in the south-eastern USA, where it is grown in rows which are periodically pruned for mulch and subsequent soil improvements, and intercropped (Jordan, 2004).
The wood of the silk tree is dense and hard. It takes a good polish and is used for making furniture. Young leaves are cooked and used as pot herbs, while cooked flowers are eaten as vegetables. Dried leaves are used as a tea substitute. In China, the flower heads are used as carminative, digestive, sedative and tonic and in the treatment of insomnia, irritability and breathlessness. The bark is anthelmintic, carminative, diuretic, sedative and vermifuge. It is used internally in the treatment of insomnia, irritability, boils and carbuncles and is applied externally to injuries and swellings. A gummy extract obtained from the plant is used as a plaster for abscesses and also as a retentive in fractures and sprains (PFAF, 1999). Leaves provide a useful soil ameliorant when incorporated or applied as a mulch (Jordan, 2004).
Uses ListTop of page
Animal feed, fodder, forage
- Fodder/animal feed
- Erosion control or dune stabilization
- Soil improvement
- Miscellaneous materials
- Source of medicine/pharmaceutical
Wood ProductsTop of page
Similarities to Other Species/ConditionsTop of page SE-EPPC (2002) reports that A. julibrissin may be confused with other bipinnately compound legumes, particularly at the seedling stage, e.g. with Chamaecrista fasciculata or Shrankia microphylla.
Prevention and ControlTop of page Mechanical Control
SE-EPPC (2002) provides details on cutting, girdling and hand-pulling of A. julibrissin. Trees are cut at ground level; this is most effective at the beginning of flowering, to prevent seed production. As A. julibrissin resprouts after cutting, this must be followed by herbicide treatment or repeated cutting of the resprouts. Girdling (ring-barking) is used on large trees where herbicide control is impractical. The bark is cut through into or below the cambium layer approximately 15 cm above the ground. Resprouting commonly occurs and must be treated as above. Young seedlings may be pulled by hand before seed production begins, and the best time to pull seedlings is after rain when the soil is loose as the entire root must be removed to ensure that resprouting from root fragments does not occur (SE-EPPC, 2002).
SE-EPPC (2002) suggests three approaches to chemical control: foliar spray method for large thickets with minimal risk to non-target species; cut-stump method for individual trees or where non-target species are at risk; and the basal bark method. The foliar spray method requires air temperature to be above 18°C to ensure the herbicides are absorbed, e.g. glyphosate or triclopyr, where desirable non-target grasses are present. Stumps may be treated if the ground is not frozen, again using glyphosate or triclopyr. In the basal bark method, a mixture of triclopyr and horticultural oil is applied to the basal parts of the tree 30-38 cm above the ground. This treatment may be applied all year except when the ground is frozen.
SE-EPPC (2002) reports that the mimosa wilt fungus Fusarium oxysporum f.sp. perniciosum may have potential for biological control, but further research is required before this method is used. Luken and Thieret (1996) identified a species of bruchid seed beetle that may be a promising agent for biological control.
ReferencesTop of page
Addlestone BJ, Mueller JP, Luginbuhl JM, Lassoie JP; Buck LE, 1999. The establishment and early growth of three leguminous tree species for use in silvopastoral systems of the southeastern USA. Special issue: Exploring the opportunities for agroforestry in changing rural landscapes. Selected papers from the 5th Biennial Conference on Agroforestry in North America, August 3-6, 1997. Agroforestry-Systems, 44(2-3):253-265.
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Jordan CF, 2004. Organic farming and agroforestry: Alley cropping for mulch production for organic farms of southeastern United States. In: Advances in Agroforestry 1: New Vista in Agroforestry. The Netherlands: Kluwer Academic Publishers, 79-90.
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Virginia Department of Conservation and Recreation, 2003. Invasive Alien Plant Species of Virginia. http://www.dcr.state.va.us/dnh/invlist.pdf.
Distribution MapsTop of page
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