Lycium ferocissimum
(African boxthorn)

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Identity

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Preferred Scientific Name

• Lycium ferocissimum Miers

Preferred Common Name

• African boxthorn

Other Scientific Names

• Lycium campanulatum E. Mey. ex C.H. Wright
• Lycium chinense Sensu Bentham non Miller
• Lycium europeum Auct.
• Lycium horridum Auct.
• Lycium macrocalyx Domin

International Common Names

• English: boxthorn; cape boxthorn

Local Common Names

• South Africa: bocksdorn; slangbessie

EPPO code

• LYUFE (Lycium ferocissimum)

Summary of Invasiveness

Top of page L. ferocissimum is a serious problem in Australia and New Zealand, after being introduced as a hedge plant due to its stout thorns and unpalatable foliage. It has, however, not been widely distributed around the world, and it is unlikely that it will be cultivated anywhere else. Birds and small mammals spread the seed widely and it is difficult to eradicate. L. ferocissimum is salt-tolerant, and can become the dominant species in vulnerable coastal and island plant communities where encroachment threatens the native flora and fauna in these habitats.

Taxonomic Tree

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• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Solanales
•                         Family: Solanaceae
•                             Genus: Lycium
•                                 Species: Lycium ferocissimum

Notes on Taxonomy and Nomenclature

Top of page The name Lycium derives from the Greek for 'thorny tree' and the English translation of ferocissimum is 'most fierce' or 'very savage', referring to the stout spines that protect the bush. There are about 80 species in the genus, approximately 50 native to the Americas and 30 are Old World species, of which over half of these are native to South Africa.

Description

Top of page L. ferocissimum is a woody, erect, perennial shrub with a deep and extensive root system (Roy et al., 1998). It grows to 3-6 m tall, with widely spreading and drooping branches. The branches divide intricately ending in short branchlets. Main stems carry a stout spine up to 15 cm in length, and branchlets carry smaller spines. The short branches carry small shoots which have clusters of leaves surrounded at the base by many small, light-brown scales. Initially, stems are smooth and light brown but become grey and rough as they mature. Leaves are almost sessile, bright green, and somewhat fleshy. Leaves are largely obovate to oblong, rounded at the top, and tapering towards the base. Leaves vary in size from 5-35 mm long by 3-12 cm wide, and rarely up to 43 long by 20 mm wide. Flowers have a corolla 12 mm across above a 10-13 mm long broadly cylindrical, 5-petalled corolla tube, and hang singly or in pairs from short stalks in the forks of leaves or on the short stems. Flowers are perfect, white to mauve, but with mauve markings from the throat. Fruit berries are approximately 10 mm in diameter with a persistent calyx. They are initially green, but ripen to bright orange or red. Berries are mostly globular but sometimes tending to ovoid.

Plant Type

Top of page Broadleaved
Perennial
Seed propagated
Shrub
Tree
Woody

Distribution

Top of page L. ferocissimum is native to the Cape region and Orange Free State, South Africa (Arnold and de Wet, 1993). It is a major weed in Australia and New Zealand (Parsons and Cuthbertson, 1992; Roy et al., 1998). In New Zealand, it is largely restricted to coastal areas in North and South Island (Webb et al., 1988), whereas in Australia it is present in all states, but only widely distributed in New South Wales, Victoria and South Australia. In dry regions it often grows around or in waterways (Marchant et al., 1987; Parsons and Cuthbertson, 1992). This species has not been distributed widely around the world, and is not naturalized in North America, Europe, Asia or elsewhere in Africa.

Distribution Table

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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.

History of Introduction and Spread

Top of page L. ferrocissimum was planted widely in Australia as a hedge plant and had become naturalized by the mid 1800s (Parsons and Cuthbertson, 1992). It was first noted as a pest in Queensland, Australia in 1917 (Fuller, 1998). It was also planted in New Zealand and was first recorded as being naturalized in 1897 (Webb et al., 1988).

Risk of Introduction

Top of page There is a only limited possibility that this species could be introduced as a hedging plant elsewhere. The greatest risk of further spread may be via natural spread by animals, or as seeds carried in the guts of traded birds or mammals. However, the risk of further introduction must be considered as small.

Habitat

Top of page It is common on roadsides, railway embankments, along watercourses and in wastelands and similar neglected areas. It rarely spreads into well-managed pasture, but can invade disturbed ground. It is particularly common and especially invasive in coastal areas and dunes, and also on offshore islands (Abbott et al., 2000).

Habitat List

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Category	Sub-Category	Habitat	Presence	Status
Terrestrial
	Terrestrial – Managed	Managed forests, plantations and orchards	Present, no further details
		Managed grasslands (grazing systems)	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
	Terrestrial ‑ Natural / Semi-natural	Natural grasslands	Present, no further details	Harmful (pest or invasive)
Littoral
		Coastal areas	Present, no further details	Harmful (pest or invasive)

Hosts/Species Affected

Top of page L. ferocissimum can invade poorly managed and degraded pasture, but is not known as a weed of agricultural or plantation crops.

Growth Stages

Top of page Seedling stage, Vegetative growing stage

Biology and Ecology

Top of page Genetics

Most species of Lycium have a chromosome number of n=12 (2n=24), though hybridization must occur as triploids and hexaploids have also been identified.

Physiology and Phenology

L. ferocissimum flowers from July to March in New Zealand (Roy et al., 1998), and similarly in the southern hemisphere summer in its native South Africa and exotic range Australia. L. ferocissimum is, however, capable of flowering and fruiting at any time given sufficient moisture. It is regarded as a halophyte (Webb et al., 1988) and its leaves may contain chemicals making them unpalatable to livestock.

Reproductive Biology

L. ferocissimum is hermaphroditic (Minne et al., 1994). Plants can flower from 2 years of age. Each berry contains up to 70 yellow or light-brown, oval, flattened seeds approximately 2.5 x 1.5 mm in size.

Environmental Requirements

L. ferocissimum is tolerant of a wide range of climates and soil types, but prefers lighter soils such as deep loams (Fuller, 1998). It is tolerant to saline soils and salt-laden sea winds, and is particularly aggressive in dry, coastal environments and islands. It is said to thrive on better soils in Queensland, Australia, but generally cannot invade dense vegetation.

Associations

Often associated with coastline vegetation and dunes although it is sometimes the only vegetation on some exposed sites (Webb et al., 1988).

Latitude/Altitude Ranges

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Air Temperature

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Rainfall

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Rainfall Regime

Top of page Summer
Winter

Soil Tolerances

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Soil drainage

• free

Soil reaction

• acid
• neutral

Soil texture

• light
• medium

Special soil tolerances

• infertile
• saline

Notes on Natural Enemies

Top of page No significant natural enemies have been recorded (Scott and Delfosse, 1992).

Means of Movement and Dispersal

Top of page Vector Transmission (Biotic)

Berries are ingested by birds and other small animals such as foxes (Fuller, 1998); the seeds remain viable after being voided. Seedlings are commonly found below habitual roosts of birds, such as under trees, fences and overhead wires. L. ferocissimum recently colonized Carnac Island, 8 km off the South Australian coast (Abbott et al., 2000) and long-distance spread by birds appears to be an effective dispersal mechanism.

Agricultural Practices

Seeds can be dispersed by the disposal of agricultural refuse. Some spread occurs through contamination of agricultural produce, gravel or mud, but these are considered of minor importance compared to spread by birds or mammals (Parsons and Cuthbertson, 1992).

Intentional Introduction

This species was intentionally introduced to Australia and New Zealand as a hedge plant in the 1800s. It is no longer grown for this purpose, but many of the non-coastal incursions have probably spread from existing hedges.

Pathway Vectors

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Plant Trade

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Plant parts not known to carry the pest in trade/transport
Bark
Bulbs/Tubers/Corms/Rhizomes
Flowers/Inflorescences/Cones/Calyx
Growing medium accompanying plants
Leaves
Roots
Seedlings/Micropropagated plants
Stems (above ground)/Shoots/Trunks/Branches
Wood

Impact Summary

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Impact

Top of page L. ferocissimum produces a dense thicket armed with spines that form an impenetrable barrier to grazing animals. Large thickets reduce the productive value of grazing land, and harbour agricultural pests such as rabbits. It can threaten productive land through gradual ingression. Spines that are cut from, or become detached from plants can penetrate the feet or pelt of grazing animals and can cause serious injury. Berries are a reservoir for fruit fly pests in Queensland, Australia (NRM, 2003). The leaves are reputed to be poisonous to poultry, and poisoning of pigs by L. ferocissimum berries has been reported (Connor, 1977).

Impact: Biodiversity

Top of page L. ferocissimum is prevalent in dry coastal vegetation in Australia (Carr, 1993) where infestations displace native plant species and encroach on the nesting sites of native birds and mammals. This weed is seriously interfering with seal breeding on beaches in the Recherche Archipelago, Western Australia, and threatens penguin breeding on Motunau Island in New Zealand. In its native range, however, L. ferocissimum has a positive effect on biodiversity as the thorns protect germinating seedlings of several valued palatable shrubs from over-grazing in the Karoo of South Africa (Todd, 2000).

Social Impact

Top of page The spines of L. ferocissimum are robust and long-lived. They can lacerate humans and puncture vehicle tyres. The berries may be poisonous if ingested (Connor, 1977).

Risk and Impact Factors

Top 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

Impact outcomes

• Negatively impacts agriculture
• Negatively impacts animal health
• Reduced native biodiversity

Impact mechanisms

• Competition - monopolizing resources
• Produces spines, thorns or burrs

Likelihood of entry/control

• Difficult to identify/detect as a commodity contaminant
• Difficult/costly to control

Uses

Top of page L. ferocissimum was originally introduced to Australia and New Zealand as a hedge plant due to its stout thorns and unpalatability to livestock. It is very rarely planted for this purpose today, but many of these hedges still exist. Bees produce honey from L. ferocissimum flowers in parts of New Zealand (Walsh, 1967).

Uses List

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Environmental

• Agroforestry

General

• Ornamental

Similarities to Other Species/Conditions

Top of page There are four Lycium species found in Australia but only one, L. australe, is native. These can be distinguished by combinations of leaf, flower and berry shape (Haegi, 1976), with L. barbarum, for example, separated by its oval leaves (Fuller, 1998). Two of these species are also naturalized in New Zealand (Webb et al., 1988). In Australia, the native tree violet (Hymenanthera dentata) has similar thorns and fruit and is occasionally confused.

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Mechanical Control

Large stands can be cleared by bulldozing, root-raking or blade ploughing or manually pulling up bushes or trees. The taproot of L. ferocissimum can produce new growth when broken and thus it can be hard to kill by such mechanical means. Physical removal of dead plants is advised because dead standing plants or trash can remain a spiny barrier for many years. Wholesale clearance will result in abundant regeneration from seeds. This can be effectively treated by further cultivation or by herbicides.

Chemical Control

Stems up to 5 cm in diameter can be successfully controlled by the careful application of herbicides in diesel to a height of 30-40 cm up the stem. Larger stems can be killed if the stem is cut, and the cut face is immediately treated with concentrated herbicide in the form of a liquid or paste. Foliar herbicide can be applied in late summer and autumn, but only when plants are actively growing (Lee, 1979) and are not effective during extended dry weather. This plant is difficult to kill and repeated applications may be necessary. Modern herbicides used for L. ferocissimum control include triclopyr, glyphosate, hexazinone, 2,4-D amine, picloram and various combinations. Use of a surfactant may reduce efficacy. Granular root-absorbed herbicides such as tebuthiuron may also be used, but as with all herbicides, use should strictly conform to label conditions and local regulations (Parsons and Cuthbertson, 1992; NRM, 2003).

Biological Control

No biological control agents have been recorded (Scott and Delfosse, 1992).

References

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Abbott I; Marchant N; Cranfield R, 2000. Long-term change in the floristic composition and vegetation structure of Carnac Island, Western Australia. Journal of Biogeography, 27(2):333-346; 67 ref.

Arnold TH; de Wet BC, 1993. Plants of southern Africa: names and distribution. Memoirs of the Botanical Survey of South Africa, No. 62. Pretoria, Republic of South Africa: Botanical Research Institute.

Carr GW, 1993. Flora of Victoria and its impact on indigenous biota. In: Foreman DB, Walsh NG, eds. Flora of Victoria, Vol. 1, Introduction. Melbourne, Australia: Inkata Press.

Connor HE, 1977. The Poisonous Plants of New Zealand. New Zealand Department of Scientific and Industrial Research Bulletin 99.

EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm

Fuller M, 1998. African boxthorn, Lycium ferocissimum. Agnote No. 590. Alice Springs, Australia: Weeds Branch.

Haegi L, 1976. Taxonomic account of Lycium (Solanaceae) in Australia. Australian Journal of Botany, 24:669-679.

Haegi L, 1986. Lycium. In: Jessop JP, Toelken HR, eds. Flora of South Australia, Part 3, edition 4. Adelaide, Australia: South Australian Government Printing Division.

Lee AN, 1979. Chemical control of African boxthorn, Lycium ferocissimum. Queensland Journal of Agricultural and Animal Sciences, 36(2):189-193

Marchant NG; Wheeler JR; Rye BL; Bennett EM; Lander NS; Macfarlane TD, 1987. Flora of the Perth Region. Perth Australia: Western Australian Herbarium, Department of Agriculture, Western Australia.

Minne L; Spies JJ; Venter HJG; Venter AM, 1994. Breeding systems in some representatives of the genus Lycium (Solanaceae). Bothalia, 24:107-110.

NRM, 2003. Department of Natural Resources and Mines, Queensland, Australia. www.nrm.qld.au/factsheets/pdf/pest/PP8.pdf.

Parsons WT; Cuthbertson EG, 1992. Noxious Weeds of Australia. Melbourne, Australia: Inkata Press, 692 pp.

Roy B; Popay I; Champion P; James T; Rahman A, 1998. An Illustrated Guide to Common Weeds of New Zealand. Canterbury, New Zealand: New Zealand Plant Protection Society.

Scott JK; Delfosse ES, 1992. Southern African plants naturalized in Australia: a review of weed status and biological control potential. Plant Protection Quarterly, 7(2):70-80

Todd SW, 2000. Patterns of seed production and shrub associations in two palatable shrub species under contrasting land use intensities. African Journal of Range and Forage Science, 17:22-26.

Walsh RS, 1967. Nectar and Pollen Sources of New Zealand. Wellington, New Zealand: National Beekeepers Association of New Zealand.

Webb CJ; Sykes WR; Garnock-Jones GJ, 1998. Flora of New Zealand, Vol. 2: Naturalised Pteridophytes, Gymnosperms, Dicotyledons. Christchurch, New Zealand: Botany Division, DSIR.

Links to Websites

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Distribution Maps

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