Title: Agapanthus praecox subsp. orientalis (F.M.Leight.) F.M.Leight.

Scientific Name: Agapanthus praecox subsp. orientalis (F.M.Leight.) F.M.Leight.

Common Names: agapanthus



Agapanthus plants Photo: Mark Imhof More images via ALA


Habitat: Native to Cape Province & Natal, South Africa (Pooley 1998), occurring in grassland, on hillsides and rocky outcrops (Batten & Bokelmann 1966, Pooley 1998) along riverbanks & lake edges (Shepherd 2004), in areas where the rainfall is more than 500 mm per annum, from sea level to 2 000 m (Notten 2004). Invades dry coastal vegetation, heathland & heathy woodland, lowland grassland & grassy woodland, dry sclerophyll forest & woodland, damp sclerophyll forest, riparian vegetation & rock outcrop vegetation (Carr et al 1992), foreshores (GCB 2003), roadsides (Walsh & Entwisle 1994), drains, low scrub, coastal cliffs, sand dunes, pasture & rocky inland cliffs (ENVBOP 2008, ARC 2004).

Distribution:



Present Distribution - Australia (source: ALA)


Invasiveness Assessment

ESTABLISHMENT


1. Germination requirements? ‘Propagate by division in late winter, or from seed in Spring or Autumn’ (Burnie et al 1998). Appears to require natural seasonal disturbances, such as warmer temperatures, for germination. It is documented to reproduce primarily by vegetative means in Victoria (Walsh & Entwisle 1994) but spreads also by seed (Blood 2001), and has been described as a ‘notorious self seeder’ (Robertson 2007).

2. Establishment requirements? Grows in full sun or under partial shade from trees (Leszczynska-Borys et al 1995). Invades dry schlerophyll forest & woodland and damp schlerophyll forest (Carr et al 1992). Able to establish under moderate canopy cover.

3. How much disturbance is required? Not specifically documented occurring in undisturbed vegetation but does establish in natural ecosystems, e.g. heathland & heathy woodland, lowland grassland & grassy woodland, dry schlerophyll forest & woodland, damp schlerophyll forest, riparian vegetation & rock outcrop vegetation (Carr et al 1992).

GROWTH / COMPETITIVE


4. Life form? Bulbous geophphyte (Carr et al 1992).

5. Allelopathic properties? No alleleopathic properties described from an extensive literature.

6. Tolerates herb pressure? ‘Plants seem to be immune to the predation of rabbits (PFAF 2008)’. Described as having ‘low’ palatability to goats (MLA 2007). Leaves and rhizomes poisonous. Sticky sap can cause severe ulceration in the mouth (Blood 2001). Evidence of minimal herbivory, but appears rarely consumed.

7. Normal growth rate? ‘Naturalise readily soon forming large clumps’ (Burnie et al 1998), ‘Fast-growing perennial’ (Gardening World Online 2002). Spreads rapidly down drainage lines (BMCC 2008). Rapid growth rate.

8. Stress tolerance to frost, drought, w/logg, sal. etc? Drought resistant (Bodkin 1986). Tolerates light frost (Notten 2004). ‘Marginally frost hardy’ (Burnie et al 1998). Grows on foreshores (GCB 2003) - tolerance to salt spray. Spreads rapidly down drainage lines (BMCC 2008) - some tolerance to waterlogging. A. africanus ‘Blooms profusely after veld fires’ (Burman & Bean 1985) and A. praecox as a bulbous geophyte with thick underground rhizomes, is assumed to also survive fire.

REPRODUCTION


9. Reproductive system? Documented as reproducing both sexually by seed and vegetatively (rhizome growth or fragments) (Blood 2001).

10. Number of propagules produced? Seeds numerous (Walsh & Entwisle 1994). No. fruits/ umbel = 30-120 (Av. = 75); seeds/fruit =6-10 (Av. = 8) - 4 inflorescences x 75 fruits x 8 seeds = 2400 seeds/plant (Leszczynska-Borys et al 1995).

11. Propagule longevity? ‘It [seed] must be kept in the refrigerator or it will perish’ (Notten 2004). An indication that seed unlikely to survive 5 years under natural conditions.

12. Reproductive period? Forms dense monocultures (ARC 2004), suggesting infestations would be self-sustaining.

13. Time to reproductive maturity? ‘Flowering can be expected from their third or fourth year’ (Notten 2004). The time taken for vegetative propagules to become separate individuals was not found described.

DISPERSAL


14. Number of mechanisms? ‘Spread in dumped garden waste and contaminated soil’ (Blood 2001), ‘water and wind’ (Carr et al 1992). ‘Spreads rapidly down drainage lines…seed may wash down waterways’ (BMCC 2008).

15. How far do they disperse? Dispersal via garden waste, contaminated soil (Blood 2001) or water (Carr et al 1992) could spread a few propagules greater than 1km, but many to 200-1000m.


Impact Assessment

RECREATION


1. Restrict human access? Clumps reach height of 60cm (Blood 2001), likely to cause minimal restriction to human access.

2. Reduce tourism? Not described as affecting recreational uses, but as a well known ornamental species (Walsh & Entwisle 1994) with the ability to form monocultures (ARC 2004) it would impact on natural area aesthetics.

3. Injurious to people? Leaves, rhizome and sap are poisonous. Can cause severe ulceration in the mouth and burning sensation and rashes on skin. Especially toxic to children (Shepherd 2004). Highly toxic.

4. Damage to cultural sites? ‘The large growing varieties will crack restricting concrete’ (Robertson 2007). Potential to cause moderate structure effect.

ABIOTIC


5. Impact flow? Described to invade terrestrial habitats (Carr et al 1992), so unlikely to impact on water flow.

6. Impact water quality? Described to invade terrestrial habitats (Carr et al 1992), so unlikely to impact on water quality.

7. Increase soil erosion? ‘A. praecox is also an excellent plant to use to stabilize a bank and to prevent erosion’ (Notten 2004). Decreases the probability of soil erosion.

8. Reduce biomass? Biomass may increase in understorey due to extensive underground root mass, dense clumping habit (BMCC 2008) and ability to form monocultures (ARC 2004).

9. Change fire regime? The presence of thick fleshy leaves (BMCC 2008) could indicate low flammability, and although not documented, in the event of fire may reduce fire intensity of the understorey.

COMMUNITY HABITAT


10(a) Impact on composition of high value EVC? EVC=Plains Grassland (E); CMA= Corangamite; Bioreg= Otway Plain; VH CLIMATE potential. ‘Forms dense monocultures that exclude all other species’ (ARC 2004). ‘Dense clumping roots of Agapanthus displace all other vegetation’ (BMCC 2008). Described as a ‘serious threat to one or more vegetation formations in Victoria’, invading lowland grassland & grassy woodland (Carr et al 1992). Monoculture; displaces all species within understorey.

10(b) Impact on medium value EVC? EVC=Coastal Headland scrub (D); CMA= Corangamite; Bioreg= Otway Ranges; VH CLIMATE potential. ‘Forms dense monocultures that exclude all other species: one cliff infestation at Piha was found to cover an area of over 1000m2’ (ARC 2004). Has spread widely along foreshores (GCB 2003) and described as a ‘serious threat to one or more vegetation formations in Victoria’, invading dry coastal vegetation (Carr et al 1992). Monoculture; displaces all species within understorey.

10(c) Impact on low value EVC? EVC= Rocky Outcrop Shrubland (LC); CMA= Glenelg Hopkins; Bioreg= Central Victorian Uplands; VH CLIMATE potential. ‘Forms dense monocultures that exclude all other species: one cliff infestation at Piha was found to cover an area of over 1000m2’ (ARC 2004). Invades rocky inland cliffs and low scrub (ARC 2004) and described as a ‘serious threat to one or more vegetation formations in Victoria’, invading rock outcrop vegetation (Carr et al 1992). Monoculture; displaces all species within understorey.

11. Impact on structure? ‘Forms dense monocultures that exclude all other species’ (ARC 2004), though largely only understorey layer affected. Major effect on <60% of the floral strata.

12. Effect on threatened flora? Dense clumping roots of agapanthus displace all other vegetation (BMCC 2008) forming monocultures (ARC 2004), However, not specifically described impacting on threatened flora.

FAUNA


13. Effect on threatened fauna? Dense clumping roots displace all other vegetation (BMCC 2008) forming monocultures (ARC 2004), with potential to reduce faunal habitat and food source, however, was not specifically described impacting on threatened fauna.

14. Effect on non-threatened fauna? Dense clumping roots displace all other vegetation (BMCC 2008) forming monocultures (ARC 2004), with potential to reduce faunal habitat and food source, however, was not specifically described impacting on native fauna.

15. Benefits fauna? ‘Leaves and rhizomes poisonous, sticky sap can cause severe ulceration in the mouth’ (Blood 2001). ‘Plants seem to be immune to the predation of rabbits’ (PFAF 2004). Described as having ‘low’ palatability to goats (MLA 2007). No benefits to native fauna were found documented - Unlikely to provide support to desirable species.

16. Injurious to fauna? Described as being toxic to humans, causing severe ulceration in the mouth and skin rashes (Shepherd 2004), and is also documented as toxic to other mammal species (P & P Inc. 2007). It presumably would have an injurious affect on some native animals if consumed, though the level of impact is unknown.

PEST ANIMAL


17. Food source to pests? ‘Plants seem to be immune to the predation of rabbits’ (PFAF 2004). Described as having ‘low’ palatability to goats (MLA 2007). Provides minimal food for pest animals.

18. Provides harbor? Its dense clumping habit to a height of 60cm (Blood 2001, BMCC 2008) and formation of monocultures (ARC 2004), gives it potential to provide short term harbour to rabbits, however, no information about its ability to provide harbour was documented in the literature.

AGRICULTURE


19. Impact yield? Documented to invade pasture and form monocultures in some habitats (ARC 2004), and it is described as having low palatability (MLA 2007) and as containing toxic properties (Shepherd 2004). However, its potential to reduce available grazing land and impact on agricultural yield is unknown.

20. Impact quality? Documented to invade pasture (ARC 2004) but there is no information to suggest it would affect agricultural quality.

21. Affect land values? Documented to invade pasture (ARC 2004) but and there is no information to suggest it would cause a change in land value.

22. Change land use? Documented to invade pasture (ARC 2004) but and there is no information to suggest it would cause a change in land use.

23. Increase harvest costs? Documented to invade pasture and form monocultures in some habitats (ARC 2004), and it is described as having low palatability (MLA 2007) and as containing toxic properties (Shepherd 2004). However, its potential to increase harvest costs due to control or animal health costs is unknown.

24. Disease host/vector? Plants were found infected with tomato spotted wilt virus in Tasmania (Wilson et al 2000) . It is unknown if this is an isolated occurrence or if plants occurring on vegetable growing properties would pose any risk.



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Assessment ratings originally made by the Victorian Department of Primary Industries.
The entry of this assessment was made possible through the generous support of The Weed's Network.






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Date: 26 October 2009; 11:41:43 AM AEDT

Author Name: Jessica Mackay
Author ID: mackayj