Taxonomic name: Asparagus densiflorus (Kunth) Jessop
Synonyms: Asparagopsis densiflorus Kunth, Asparagus sprengeri Regel, Protasparagus densiflorus (Kunth) Oberm.
Common names: asparagus Fern, asperge de Sprenger (French), bushy asparagus, regal fern, smilax, sprengeri fern, Sprenger's asparagus fern
Organism type: herb Asparagus densiflorus, commonly known as asparagus fern, is not a true fern. It reproduces by seed. A. densiflorus is known to invade a variety of habitats, and its impacts include smothering of forest understory and ground cover and preventing the regeneration of canopy species. Description
Asparagus densiflorus is described as a spreading perennial herb with a fine texture and stiff, upright habit. The stems which are stiff and erect and a bit woody are armed with stiff spines, they emerge directly from the ground. The plant grows rapidly up to a height of 60cms. The leaves of the plant are small and scale like, what we consider to be leaves are actually narrow, light green, leaf-like branchlets called cladophylls which can reach lengths of 2.5cms. The needles are clustered at branch nodes. The flowers are small, white or pinkish white, and fragrant; the fruit which are quite showy are bright red in colour about 8mm in diameter, and are typically 3 seeds per fruit (The University of Florida, 2002; Gilman, 1999). Similar Species
Asparagus spp.
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Occurs in:
coastland, natural forests, planted forests Habitat description
PIER (2005) reports that Asparagus densiflorus can be found on, "Dry to moist forests and openings. In Australia it has invaded coastal, littoral rainforest, rainforest, frontal dunes and sclerophyll forest and coastal heath." The Australian Weeds Committee (2004) states that, "A. densiflorus is a persistent weed of urban bushland. It is shade tolerant and grows best in shaded areas where other vegetation has been removed. It is also often found growing near abandoned houses or near habitation where pieces have been dumped." Jamieson (2002) states that, "A. densiflorus grows in most soils and is fairly drought tolerant, but does much better in soil which is rich in organic matter and is watered regularly." The University of Florida (2002) has gathered the following information on A. densiflorus: "Cold hardy to -1°C (30°F) (Broschat and Meerow 1991). Thrives in any well-drained soil (Stresau 1986). Grows in low to high light conditions, has low nutrient requirements, and tolerates drought (Broschat and Meerow 1991). A. densiflorus is also noted as having "good" salt tolerance (Hunt 1977).” General impacts
The Bay of Plenty Regional Council (UNDATED) states that, "A. densiflorus has the potential to be similar to climbing asparagus in its ability to smother forest understory to a height of 2.5 - 5 m; this species can also smother ground cover and prevent regeneration of canopy species." Uses
Asparagus densiflorus is excellent as a groundcover ornamental, especially in full sun (Jamieson, 2002). Geographical range
Native range: South Africa (University of Florida. 2002).
Known introduced range: Australasia-Pacific region, the Caribbean, Europe, and North America (Batianoff and Frakes,1997; Bahamas Environment Science & Technology Commission, UNDATED; Singh et al. 1999; University of Florida. 2002)." Introduction pathways to new locations
For ornamental purposes: The widespread use of this plant in ornamental settings coupled with production of large numbers of fruit that are undoubtedly attractive to birds which will continue to contribute to the plants spread (Bishop Museum, 1999).
Local dispersal methods
Consumption/excretion: PIER (2005) reports that, "Asparagus densiflorus is probably dispersed by fruit-eating birds." Management information
Preventative measures: A Risk assessment of Asparagus densiflorus for the Pacific region was prepared by Pacific Island Ecosystems at Risk (PIER) using the Australian risk assessment system (Pheloung, 1995). The result is a score of 15 and a recommendation of: reject the plant for import (Australia) or species likely to be of high risk (Pacific).
A Risk assessment of Asparagus densiflorus for Australia was prepared by Pacific Island Ecosystems at Risk (PIER) using the Australian risk assessment system (Pheloung, 1995). The result is a score of 3 and a recommendation of: the plant requires further evaluation. Chemical: The Regional Weeds Advisory Committee (2004) states that, "Asparagus species have often been controlled using the "crowning" technique where the above ground part of the plant is cut from the root system and hung up off the ground. Tubers can be painted with glyphosate. Runners near the ground can be gathered up and their main root systems removed. Regrowth needs to be controlled whilst it is actively growing (preferably between flowering and fruiting) with such techniques as foliar spraying with glyphosate (1 part glyphosate to 75 parts water) or metsulfuron methyl (1-2g in 10L of water)." Biological: The Regional Weeds Advisory Committee (2004) states that in Australia, "A. densiflorus is attacked by a chalcid wasp (Family: Chalcidae) and a moth larva. A rust fungus severely damages the fruit. Leaves are severely damaged by a thrip and the larvae of a geometrid wasp. Stems are galled by two chalcid species." Each of these species may have a biological control application, but further research is needed. Crioceris spp. is a potential biological control agent for Asparagus spp. and has the possibility of being effective on A. densiflorus also (Witt and Edwards, 2001). Cultural: The Regional Weeds Advisory Committee believes there is a lack of awareness in the public about many coastal weeds, including A. densiflorus. Many invasive coastal species are still ignorantly being planted widely in backyards and as ornamentals. The authors believe that, "Education programs will focus on increasing awareness of the threat caused by the species, knowledge of identification and control techniques and local success stories. Education programs will need to focus on both the regional level and local level where examples of local problems can be seen / promoted." Nutrition
Asparagus densiflorus plants have extensive root systems with fairly large tubers, which are used in nature to provide food during long periods of drought in summer (Jamieson, 2002). Reproduction
Conover (2000) states that, "Plants in the genus Asparagus such as A. setaceus and A. densiflorus are called ferns, but are not true ferns since they produce seeds and not spores." Csurhes and Edwards (1998) state that, "The plant produces large numbers of fleshy, red berries which usually each contain a single seed. The fruit is probably dispersed by birds." Lifecycle stages
Seeds may germinate at any time of the year providing moisture is available, but there is a major flush in spring and a smaller one in autumn. Growth rate is slow until the root system is well established, increasing rapidly subsequently. Tuber begin to form on the rhizomes and roots about mid-summer. Although plants do not always flower in their first year, flowering usually commences in October and continues until February or march and in some situations, continues to May or June. Fruit may be present on plants all the year. In established plants, new growth forms on the rhizomes and tubers in spring increasing the size of the effected area.(Parsons and Cuthbertson 1992). Reviewed by: Dennis Gannaway, National Bridal Creeper Management Coordinator. Department of Water, Land and Biodiversity Conservation (DWBLC) Government of South Australia, Australia Principal sources: University of Florida, 2002. Liliaceae/Lily Family Asparagus densiflorus (Kunth) Jessop. Florida Exotic Pest Plant Council.
Regional Weeds Advisory Committee, 2004. Draft Regional Weed Management Plan 1.1 Plan Title: Coastal weeds
Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG) with support from the Terrestrial and Freshwater Biodiversity Information System (TFBIS) Programme (Copyright statement)
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Last Modified: Thursday, 23 March 2006
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