Elaeagnus pungens (thorny olive)
- 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
- Air Temperature
- Rainfall Regime
- Soil Tolerances
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Causes
- Impact Summary
- Economic Impact
- Environmental Impact
- Threatened Species
- Social Impact
- Risk and Impact Factors
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- Links to Websites
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Elaeagnus pungens Thunb., 1784
Preferred Common Name
- thorny olive
Other Scientific Names
- Elaeagnus pungens var. simonii (Carrière) Rehder
- Elaeagnus simonii Carrière
International Common Names
- English: leathery silver-bush; pungent elaeagnus; silverberry; silverthorn; spotted elaeagnus; thorny elaeagnus
- Chinese: hu tui zi
Local Common Names
- Germany: Ölweide, Dornige
- Japan: nawashiro-gumi
- ELGPU (Elaeagnus pungens)
Summary of InvasivenessTop of page
E. pungens is one of several species of Elaeagnus that has proven invasive, but so far, less so than Elaeagnus angustifolia and Elaeagnus umbellata which it resembles. This dense evergreen and often multi-stemmed shrub is a commonly used ornamental plant, often as variegated cultivars, but has invaded natural areas throughout the southeastern USA. It is very tolerant of wind, salt and shade, but will invade both in open areas and in forests. The fruit is widely consumed by animals and can spread rapidly.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Elaeagnales
- Family: Elaeagnaceae
- Genus: Elaeagnus
- Species: Elaeagnus pungens
Notes on Taxonomy and NomenclatureTop of page
Elaeagnus is placed in its own family, the Elaeagnaceae, also containing the genera Hippophae and Shepherdia. There are about 80 species within the genus with a wide distribution in eastern Asia (Zheng et al., 2006). Elaeagnus pungens is placed in section Sempervirentes (Tzvelev, 2002). Being a respected ornamental species, there are a number of cultivars including probably the most widespread, cv. Maculata, but also Aurea, Dicksonii, Frederici, Fruitlandii, Gold Rim and Variegata amongst others. These are sometimes given higher ranks such as form or variety, and subspecies have also been proposed. For the purposes of this datasheet, a single undivided species is accepted with numerous cultivars. It is most commonly known as the thorny olive or silverberry.
DescriptionTop of page E. pungens is an evergreen densely branched shrub commonly 3-4 m, but it can be as small as 1 m, and occasionally up to 8 m tall. Spines are frequent on the stems. Young branches densely brown scaly, pubescent when young. Leaves thick and leathery, silver-brown, alternate, oval, elliptical or oblong, 5-10 cm long and 1.8-3.5 (-5) cm wide, with dense whitish scales also often brown, glabrous and glossy above, scaly underneath, lateral veins 7-9 each side of midrib, base rounded, irregular undulate margins, apex obtuse to bluntly acute. Petioles robust, 4-5 (-15) mm long. Flowers fragrant, silvery-white to brown, tubular and 1 cm long, few (1-3), in axillary clusters, pedicel 5-8 mm and scaly brown, calyx tube 6-7 mm long and abruptly narrowed at base, lobes ovate, apex rounded. Fruit oblong, 1.0-1.5 cm, brown scaly containing one nut, white changing to red with spotted brown scales when ripe (adapted from Miller, 2003; Flora of China Editorial Committee, 2008).
Plant TypeTop of page Broadleaved
DistributionTop of page
E. pungens is native to China and Japan. It has been introduced to the eastern and southeastern USA were it is widely reported, is noted in New Zealand, and also in some European countries with unconfirmed reports from others. Noting its ornamental value and tolerance to drought and saline conditions, it is likely to be present in many more countries than is indicated, especially in northern Europe, but also around the Mediterranean, western USA, Canada, and elsewhere.
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||Reference||Notes|
|China||Present||Present based on regional distribution.|
|-Anhui||Present||Native||Not invasive||USDA-ARS, 2008|
|-Fujian||Present||Native||Not invasive||USDA-ARS, 2008|
|-Guangdong||Present||Native||Not invasive||USDA-ARS, 2008|
|-Guangxi||Present||Native||Not invasive||USDA-ARS, 2008|
|-Guizhou||Present||Native||Not invasive||USDA-ARS, 2008|
|-Hubei||Present||Native||Not invasive||USDA-ARS, 2008|
|-Hunan||Present||Native||Not invasive||USDA-ARS, 2008|
|-Jiangsu||Present||Native||Not invasive||USDA-ARS, 2008|
|-Jiangxi||Present||Native||Not invasive||USDA-ARS, 2008|
|-Zhejiang||Present||Native||Not invasive||USDA-ARS, 2008|
|Georgia (Republic of)||Present||Introduced||Invasive||USDA-NRCS, 2008|
|Israel||Present||Introduced||Not invasive||Hagiladi et al., 1989|
|Japan||Present||Native||Not invasive||USDA-ARS, 2008|
|-Honshu||Present||Native||Not invasive||USDA-ARS, 2008|
|-Kyushu||Present||Native||Not invasive||USDA-ARS, 2008|
|-Shikoku||Present||Native||Not invasive||USDA-ARS, 2008|
|USA||Present||Native||Not invasive||USDA-ARS, 2008; USDA-NRCS, 2008|
|-North Carolina||Present||Introduced||USDA-NRCS, 2008|
|-South Carolina||Present||Introduced||Invasive||USDA-NRCS, 2008|
|Argentina||Present||Introduced||Carmona and Wright, 1999||Ornamental, in La Plata and Buenos Aires|
|Germany||Present||Introduced||Not invasive||Houtman, 2004|
|Italy||Present||Introduced||Devecchi and Remotti, 2004||Ornamental|
|Netherlands||Present||Introduced||Christenhusz and Uffelen, 2001||Naturalized in some cases|
|Poland||Present||Introduced||Not invasive||Kubus, 2003|
|New Zealand||Present||Introduced||Clawson et al., 1997|
History of Introduction and SpreadTop of page
E. pungenswas first introduced into the USA in 1830 as an ornamental, and it was thought to have been introduced into Europe between 1829 and 1866, first to the Netherlands, by the Bavarian physician Philipp von Siebold who introduced numerous garden plants from Japan into Europe (Christenhusz and Uffelen, 2001). It was also introduced to New Zealand, and to Israel (Hagiladi et al., 1989), though exact dates are not known.
Risk of IntroductionTop of page
E. pungens is on the Florida and South-East Exotic Plant Pest Council list of invasive plants (USDA-NRCS, 2008), and is also on exotic pest lists for several other states including Alabama, Georgia, South Carolina, Tennessee and Virginia. As a highly valued ornamental it is highly likely to continue to be introduced as any number of the existing or future selected cultivars.
HabitatTop of page
In its native range, E. pungens is often found on open slopes, roadsides or thickets, often near the sea and generally below 1000 m (Flora of China Editorial Committee, 2008). Where introduced and invasive it is also found in scrub and shrublands, and natural forests.
Habitat ListTop of page
|Terrestrial – Managed||Rail / roadsides||Present, no further details||Harmful (pest or invasive)|
|Terrestrial ‑ Natural / Semi-natural||Natural forests||Present, no further details||Harmful (pest or invasive)|
|Natural grasslands||Present, no further details||Natural|
|Scrub / shrublands||Present, no further details||Harmful (pest or invasive)|
|Scrub / shrublands||Present, no further details||Natural|
|Coastal areas||Present, no further details||Harmful (pest or invasive)|
|Coastal areas||Present, no further details||Natural|
|Coastal dunes||Present, no further details||Harmful (pest or invasive)|
|Coastal dunes||Present, no further details||Natural|
Biology and EcologyTop of page Genetics
A number of cultivars have been selected and propagated, mostly for variegated foliage. Of these, cv. Maculata and cv. Dicksonii are slower growing variegated forms that also produce good fruit crops, cv. Frederici has especially large fruit 25 mm long, and there are other cultivars including Aurea, Clemson Variegated, Fruitlandii, Gold Rim, Hoksuba Fukurin, Tricolor and Variegata. Frederici is an old cultivar and may have been the original sent to the Netherlands by von Siebold in the mid 1800s (Houtman, 2004). The cultivated hybrid Elaeagnus x ebbingei arose from a cross between E. macrophylla, and pollen from E. pungens and was distributed in 1938 through M Koster and Sons of Boskoop, the Netherlands (Houtman, 2004). Chromosome numbers are not reported.Reproductive Biology
The scented flowers are hermaphrodite and are pollinated by bees.Physiology and Phenology
Although commonly described as an evergreen, it may be deciduous in some circumstances. In its native range in China it flowers in September-December and fruits in April-June (Flora of China Editorial Committee, 2008). Where invasive in the USA it flowers in November-February and fruits in April-May. It is a nitrogen-fixing species, via an association with actinomycete fungi. After germination it produces dense multiple stems, with short shoots and small leaves that become branched or unbranched thorns 1-4 cm long. In the second year, lateral branches are produced that are followed by flowers in the autumn (Miller, 2003). It is extremely wind resistant and salt resistant (Houtman, 2004). Associations It is a nitrogen-fixing species, in association with actinomycete fungi, Frankia spp. (Dommergues et al., 1999), that also nodulate Hippophae and Shepherdia, but not by strains that colonize other actinorhizal plants such as Casuarina and Alnus. Inocula is available for Elaeagnus species, although inoculation may not be necessary since most plants spontaneously nodulate in the nursery or upon planting in the field, and unlike Rhizobium, Frankia survive in the soil for long periods without the presence of host plants. Specific E. pungens strains were identified by Fukumoto et al. (1995). E. pungensis a species of warm temperate climates, and drought tolerant but can grow in most soils. It prefers a variety of soil types but prefers well-drained soils, and can tolerate infertile and very heavy soils, acid and alkaline conditions, and exposure to salt winds.
It is a nitrogen-fixing species, in association with actinomycete fungi, Frankia spp. (Dommergues et al., 1999), that also nodulate Hippophae and Shepherdia, but not by strains that colonize other actinorhizal plants such as Casuarina and Alnus. Inocula is available for Elaeagnus species, although inoculation may not be necessary since most plants spontaneously nodulate in the nursery or upon planting in the field, and unlike Rhizobium, Frankia survive in the soil for long periods without the presence of host plants. Specific E. pungens strains were identified by Fukumoto et al. (1995).Environmental Requirements
E. pungensis a species of warm temperate climates, and drought tolerant but can grow in most soils. It prefers a variety of soil types but prefers well-drained soils, and can tolerate infertile and very heavy soils, acid and alkaline conditions, and exposure to salt winds.
ClimateTop of page
|C - Temperate/Mesothermal climate||Preferred||Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C|
|Cf - Warm temperate climate, wet all year||Preferred||Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year|
|Cs - Warm temperate climate with dry summer||Preferred||Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers|
|Cw - Warm temperate climate with dry winter||Preferred||Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters)|
Air TemperatureTop of page
|Parameter||Lower limit||Upper limit|
|Absolute minimum temperature (ºC)||-20||0|
|Mean annual temperature (ºC)||10||22|
|Mean maximum temperature of hottest month (ºC)||15||25|
|Mean minimum temperature of coldest month (ºC)||0||10|
RainfallTop of page
|Parameter||Lower limit||Upper limit||Description|
|Dry season duration||0||3||number of consecutive months with <40 mm rainfall|
|Mean annual rainfall||500||3000||mm; lower/upper limits|
Rainfall RegimeTop of page Bimodal
Soil TolerancesTop of page
Special soil tolerances
Natural enemiesTop of page
Notes on Natural EnemiesTop of page
There are few records of pests and diseases specifically attacking E. pungens, though further investigation into horticultural diseases affecting ornamental plants would yield additional results. Colletotrichum gloeosporioides [Glomerella cingulata] was first identified as the causal agent of anthracnose in Argentina by Carmona and Wright (1999), and E. pungens was first identified as a new host record for Fusarium solani by Miller (1997).
Means of Movement and DispersalTop of page Vector Transmission (Biotic)
E. pungensseeds are dispersed by animals (Miller, 2003). Intentional Introduction It was introduced intentionally as an ornamental species around the world.
It was introduced intentionally as an ornamental species around the world.
Pathway CausesTop of page
Impact SummaryTop of page
|Economic/livelihood||Positive and negative|
Economic ImpactTop of page
As a valued and widely commercialised ornamental species, it has a clear positive economic impact as a traded product in the horticultural industry, though no data is available. However, native alternatives are available in all countries where it is introduced and currently sold.
Environmental ImpactTop of page
E. pungens invades natural environments and suppresses native vegetation. There are also unconfirmed reports of it being able to develop a climbing habit, and that it can climb to the tops of trees in northern Italy.
Threatened SpeciesTop of page
Social ImpactTop of page
The only social impacts are positive, from the aesthetic value as an ornamental species, and especially in coastal gardens in northern Europe where few other variegated plants can tolerate the harsh conditions.
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
- Pioneering in disturbed areas
- Highly mobile locally
- Fast growing
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Has high genetic variability
- Damaged ecosystem services
- Ecosystem change/ habitat alteration
- Modification of fire regime
- Modification of nutrient regime
- Modification of successional patterns
- Monoculture formation
- Reduced native biodiversity
- Threat to/ loss of native species
- Transportation disruption
- Competition - monopolizing resources
- Competition - shading
- Rapid growth
- Highly likely to be transported internationally deliberately
- Difficult/costly to control
UsesTop of page
E. pungens is mainly used for ornamental purposes, and is still a valued ornamental plant in the south-eastern USA from Maryland to Florida, where it is often used in parking lots and in highway medians. In northern Europe, its extreme wind resistant and salt resistant makes it one of the most preferred plants for coastal areas, especially the variegated cultivars (Houtman, 2004).
Uses ListTop of page
- Wildlife habitat
Human food and beverage
- Propagation material
Similarities to Other Species/ConditionsTop of page
E. pungens closely resembles the two other commonly introduced Elaeagnus spp., E. angustifolia and E. umbellata but the latter are generally deciduous and have thin, non-leathery leaves.
Prevention and ControlTop of page
There are few reports of specific control methods for E. pungens, however, it could be assumed that cultural, mechanical and chemical treatments effective on the related E. angustifolia and E. umbellata would also be useful on E. pungens, especially those for E. umbellata as it occupies more similar climates and habitats. Control will need monitoring and repeated treatments to achieve success, and because seeds can be dispersed long distances by animals, it should also be eradicated in surrounding areas. Control can likely be achieved through eradication of individuals by hand pulling or spot applications of herbicide.
Hand-pulling of smaller plants would be effective, but as plants will resprout, mechanical or physical means that do not remove the roots are unlikely to be effective. Fire may also be appropriate (Munger, 2003).
Zheng et al. (2006) have identified a range of natural enemies of E. pungens from its native range in China, some of which may prove effective as biological control agents.
Several herbicides have been used alone or in combination to provide effective control of E. umbellata and which may also prove effective on E. pungens (see Sather and Eckardt, 2001; Munger, 2003). Dicamba, glyphosate or 2,4-D (but not metsulfuron methyl) have been used as effective foliar-applied herbicides especially on shorter plants. On larger plants, glyphosate, triclopyr and/or 2,4-D are used effectively on regrowth; also basal-bark applications of triclopyr. In an invaded tree plantation in Illinois, USA, triclopyr reduced E. umbellata from 12.5 to 3.9 stems/m2, but it is recommended that intensive control efforts focusing on relatively small areas in large well-established populations are only moderately effective and control efforts must be repeated every 5 years to achieve eradication (Edgin and Ebinger, 2001).
ReferencesTop of page
Carmona MA, Wright ER, 1999. Occurrence of anthracnose on eleagnus under water deficit in Argentina. (Ocurrencia de la antracnosis del eleagno en condiciones de stress hídrico en Argentina.) Fitopatologia Brasileira, 24(4):574.
Hagiladi A, Ben-Jaacov J, Eliasaf A, 1989. Damage caused by wind-borne salts to landscape plants and its prevention by a wind-controlled sprinkler system. Journal of Environmental Horticulture, 7(3):85-87.
Miller JH, 2003. Nonnative invasive plants of southern forests: a field guide for identification and control. General Technical Report - Southern Research Station, USDA Forest Service, No.SRS-62:iv + 93 pp.
USDA-ARS, 2008. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx
Zheng H, Wu Y, Ding J, Binion D, Fu W, Reardon R, 2006. Invasive plants of Asian origin established in the US and their natural enemies. Volume 1. Chinese Academy of Sciences and USDA Forest Service. http:\\www.us/foresthealth/technology/pdfs/IPAOv1ed2.pdf
ContributorsTop of page
29/02/08 Original text by:
Nick Pasiecznik, Consultant, France
Distribution MapsTop of page
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