Pacific Island Ecosystems at Risk (PIER)


Agapanthus praecox


RISK ASSESSMENT RESULTS: High risk, score: 12


Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.
Information on Risk Assessments
Original risk assessment
Agapanthus praecox Willdenow. Family: Liliaceae
Syn: Agapanthus longispathus, A. orientalis, A. umbellatus
Common name(s): common Agapanthus, blue lily, bloulelie

Answer

Score

1.01

Is the species highly domesticated? (If answer is 'no' then go to question 2.01)

y=-3, n=0

n

0

1.02

Has the species become naturalized where grown?

y=-1, n=-1

 

1.03

Does the species have weedy races?

y=-1, n=-1

 

2.01

Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”

See Append 2

1

2.02

Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2

1

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

y

1

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

n

0

2.05

Does the species have a history of repeated introductions outside its natural range? y=-2

?=-1, n=0

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

 

y

2

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

n

0

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

n

0

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

y

3

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

n

0

4.01

Produces spines, thorns or burrs

y=1, n=0

n

0

4.02

Allelopathic

y=1, n=0

n

0

4.03

Parasitic

y=1, n=0

n

0

4.04

Unpalatable to grazing animals

y=1, n=-1

4.05

Toxic to animals

y=1, n=0

4.06

Host for recognized pests and pathogens

y=1, n=0

n

0

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

y

1

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

n

0

4.10

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

1

4.11

Climbing or smothering growth habit

y=1, n=0

n

0

4.12

Forms dense thickets

y=1, n=0

y

1

5.01

Aquatic

y=5, n=0

n

0

5.02

Grass

y=1, n=0

n

0

5.03

Nitrogen fixing woody plant

y=1, n=0

n

0

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

y

1

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

0

6.02

Produces viable seed.

y=1, n=-1

y

1

6.03

Hybridizes naturally

y=1, n=-1

y

1

6.04

Self-compatible or apomictic

y=1, n=-1

6.05

Requires specialist pollinators

y=-1, n=0

n

0

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

y

1

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

3

0

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

n

-1

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

1

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

-1

7.04

Propagules adapted to wind dispersal

y=1, n=-1

y

1

7.05

Propagules water dispersed

y=1, n=-1

y

1

7.06

Propagules bird dispersed

y=1, n=-1

n

-1

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

-1

7.08

Propagules survive passage through the gut

y=1, n=-1

n

-1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

n

-1

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-1

8.03

Well controlled by herbicides

y=-1, n=1

n

1

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y=1, n=-1

y

1

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

Total score:

12

Supporting data:

Notes

Source

1.01

No evidence of substantial divergence from wild varieties.

 

1.02

Answer not scored because conditions for scoring (1.01 must = y) were not met

 

1.03

Answer not scored because conditions for scoring (1.01 must = y) were not met

 

2.01

Not native to tropical or subtropical regions but is grown successfully in Hawaii "African lilies are important and abundant ornamentals in Hawaii, and the visual effect is striking. They are popular as massed bedding plants or ground covers and in mixed home flower gardens."

Staples, G.W. and D. R. Herbst. 2005. A Tropical Garden Flora. Plants Cultivated in the Hawaiian Islands and Other Tropical Places. Bishop Museum Press, Honolulu, HI. 908 pages

2.02

Areas outside of native range where African lily is in cultivation are not well knowndue to hybridization and taxonomic uncertainty (see 6.03 for more information)

 

2.03

(1)"A. praecox will tolerate light frost, but is hardy only in the milder parts of the Northern Hemisphere, like the southwest of England and in the Mediterranean. In areas with extreme winter temperatures they are best grown in the cool greenhouse, or in containers that can be taken into a greenhouse during winter" (2)"USDA Zone 8b: to -9.4 °C (15 °F) USDA Zone 9a: to -6.6 °C (20 °F) USDA Zone 9b: to -3.8 °C (25 °F) USDA Zone 10a: to -1.1 °C (30 °F) USDA Zone 10b: to 1.7 °C (35 °F)" (3)"Prolific seeder, dispersing effectively and germinating densely. Long-lived, and tolerates hot or cold temperatures, wet or drought conditions, wind, salt, poor soils, moderate-shade, heavy damage, and sea immersion of rhizomes and seeds."

(1)South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/ (2)Whitinger, D. Website: Dave's Garden. Accessed 2008. http://davesgarden.com/ (3)Weedbusters Weed Information New Zealand. Accessed 2008. http://weedbusters.co.nz/weed_info/weed_list.asp

2.04

"African lily to native to the Cape region of South Africa."

Staples, G.W. and D. R. Herbst. 2005. A Tropical Garden Flora. Plants Cultivated in the Hawaiian Islands and Other Tropical Places. Bishop Museum Press, Honolulu, HI. 908 pages

2.05

Widely grown as ornamentals "I doubt that there is a South African gardener alive that has not come across an agapanthus somewhere! They line our roads, and are in most gardens and parks, from the tall globular-headed ones to the ever-shrinking dwarf cultivars now available at garden centres. Most of the agapanthus that are grown are cultivars or hybrids of Agapanthus praecox"

South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/

3.01

(1)Yes, in Australia. "Agapanthus praecox ssp. Orientalis A garden escape, Agapanthus threatens the iconic ‘Three Sisters’ in the World Heritage-listed Blue Mountains, NSW. There are also signs this popular garden plant may be spreading in cold parts of Victoria, South Australia, Tasmania and Western Australia." (2)Yes, in New Zealand "Which habitats is it likely to invade? : Most coastal sites, banks, cliffs, gumland, consolidated sand, fernland, shrubland, and bush margins."

(1)CRC for Australian Weed Management. Webpage: Weeds Image Gallery. Accessd 2008. http://www.weeds.crc.org.au/main/image_gallery_page1.html (2)Weedbusters Weed Information New Zealand. Accessed 2008. http://weedbusters.co.nz/weed_info/weed_list.asp

3.02

No evidence

3.03

No evidence

3.04

(1)"Impact on Bushland Spreads rapidly down drainage lines, but will also grow in dry areas. Dense clumping roots displace all other vegetation." (2)"Invades gardens, bushland and roadside areas. Tolerates a wide range of conditions from damp to very dry. Takes over anddisplaces indigenous grasses and groundcovers. It also attracts large numbers of snails and slugs." (3)"Forms pure stands, excluding all other species and becoming the terminal species almost everywhere it grows. It causes massive biodiversity loss, especially of rare coastal herb, grass and shrub species." (4)"The South African lily, Agapanthus praecox ssp. Orientalis, is a minor weed in New Zealand. It was not naturalised in the late 1990s in Tasmania, but it is now regarded as one of the worst environmental weeds in some parts of Tasmania"

(1)Produced by the Shire of Yarra Ranges in the interests of a healthier environment. Unadated. Environmental Fact Sheet No. 10: Agapanthus. This list has been obtained from the Yarra Ranges Planning Scheme Local Policy 22.12 VEGETATION PROTECTION (2)CRC for Australian Weed Management. Webpage: Weeds Image Gallery. Accesse 2008. http://www.weeds.crc.org.au/main/image_gallery_page1.html (3)Weedbusters Weed Information New Zealand. Accessed 2008. http://weedbusters.co.nz/weed_info/weed_list.asp (4)Hingston, A. 2006. Weeds that have Become More Invasive in Tasmania Since the Introduction of Bumblebees. Available on-line at: http://www.zeta.org.au/~anbrc/bumblebees-and-weeds.html

3.05

No evidence although Agapanthus africanus may be a "sleeper" weed

Randall, R.P. 2002. A Global Compendium of Weeds. Shannon Books, Melbourne

4.01

No, has "rhizomatous roots, strap-like leaves and an umbellate inflorescence on a stalk held above the leaves."

Webpage: Plants for A Future: Edible, Medicinal ans Useful Plants for a Healthier World. Accessed 2008. http://www.pfaf.org/index.php

4.02

No evidence

4.03

Not parasitic

USDA Animal Plant Health Inspection Service Staff. 2008. Parasitic Plant Genera List

4.04

Possibly, "Plants seem to be immune to the predations of rabbits"

Webpage: Plants for A Future: Edible, Medicinal ans Useful Plants for a Healthier World. Accessed 2008. http://www.pfaf.org/index.php

4.05

Possibly, poisonous to tortoises

American Tortoise Rescue. Webpage: Poisonous plants. Accessed 2008. http://www.tortoise.com/facts_and_information/poison_plants.html

4.06

"Agapanthus praecox is generally pest- and disease-free. Foliage may be attacked by red spider mites, thrips, and mealy bug but need only be sprayed if infestation is severe. Agapanthus are famous for harbouring snails, although the snails do not seem to cause any damage to the plants themselves. The best way to combat them is to remove them by hand or to keep ducks. Botrytis, visible as brownish lesions, may attack the flowers preventing them from opening. There is no cure, it can only be prevented by spraying before and after the buds break open. The foliage may be attacked by the fungus Macrophoma agapanthii causing die-back of the leaves, and in severe cases can be combatted with a fungicide like mancozeb or captab as a full cover spray."

South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/

4.07

"Agapanthus is suspected of causing haemolytic poisoning in humans, and the sap causes severe ulceration of the mouth."

South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/

4.08

Unknown

4.09

(1)"It can grow in semi-shade (light woodland) or no shade … It only flowers freely if it is in a very sunny position" (2)"It prefers full sun, and some cultivars will flower in semi-shade."

(1)Webpage: Plants for A Future: Edible, Medicinal ans Useful Plants for a Healthier World. Accessed 2008. http://www.pfaf.org/index.php (2)South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/

4.10

(1)"Agapanthus praecox is easy to grow and it does well even in the poorest of soils" (2)"The plant prefers light (sandy) and medium (loamy) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils … It requires moist soil. The plant can tolerate maritime exposure."(3)"Prolific seeder, dispersing effectively and germinating densely. Long-lived, and tolerates hot or cold temperatures, wet or drought conditions, wind, salt, poor soils, moderate-shade, heavy damage, and sea immersion of rhizomes and seeds."

(1)South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/ (2)Webpage: Plants for A Future: Edible, Medicinal ans Useful Plants for a Healthier World. Accessed 2008. http://www.pfaf.org/index.php (3)Weedbusters Weed Information New Zealand. Accessed 2008. http://weedbusters.co.nz/weed_info/weed_list.asp

4.11

No, a lily

4.12

"Forms pure stands, excluding all other species and becoming the terminal species almost everywhere it grows. It causes massive biodiversity loss, especially of rare coastal herb, grass and shrub species."

Weedbusters Weed Information New Zealand. Accessed 2008. http://weedbusters.co.nz/weed_info/weed_list.asp

5.01

Terrestrial

5.02

Not Poaceae

5.03

Not Nitrogen-fixing

5.04

Yes. "Perrennial herbs with thickened rootstocks; roots fleshy."

Staples, G.W. and D. R. Herbst. 2005. A Tropical Garden Flora. Plants Cultivated in the Hawaiian Islands and Other Tropical Places. Bishop Museum Press, Honolulu, HI. 908 pages

6.01

"The Agapanthaceae is a monotypic family (consists of only one genus) that is endemic to southern Africa, i.e. Agapanthus occurs naturally nowhere else on Earth. The six variable species are widespread in all the provinces of South Africa except for the Northern Cape, and in Lesotho, Swaziland and Mozambique, but not in Namibia or Botswana. They occur only in areas where the rainfall is more than 500 mm (20 inches) per annum, from sea level to 2 000 m (7000 ft), with a distribution range that extends from the Cape Peninsula in the southwest, along the southern and eastern coast of southern Africa then inland and northwards into the mountainous regions south of the Limpopo River."

South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/

6.02

"Propagation is by seed or division. Because agapanthus plants hybridize freely with each other, and are all in flower at the same time, you can be sure that there will be hybrids from seed harvested in the Kirstenbosch Garden. To get pure seed of any Agapanthus species it would have to be habitat collected or pollinated under strictly controlled conditions."

South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/

6.03

"Agapanthus species are easily able to hybridize with each other, particularly when grown in close proximity and as a result, a bewildering array of garden hybrids have arisen."

South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/

6.04

Possible as the flowers are "hermaphrodite (have both male and female organs) and are pollinated by Bees."

Webpage: Plants for A Future: Edible, Medicinal ans Useful Plants for a Healthier World. Accessed 2008. http://www.pfaf.org/index.php

6.05

"It is possible that bumblebees have contributed to the sudden invasiveness of A. praecox in Tasmania. Recent research by Andrew Hingston has shown that bumblebees are the most common visitors to this weed's flowers; bumblebees contact the stigma and anthers significantly more often than honeybees do; and bumblebees carry significantly more A. praecox pollen than honeybees do"

Hingston, A. 2006. Weeds that have Become More Invasive in Tasmania Since the Introduction of Bumblebees. Available on-line at: http://www.zeta.org.au/~anbrc/bumblebees-and-weeds.html

6.06

"Agapanthus is easily propigated by division of old clumps and removal of offsets"

Staples, G.W. and D. R. Herbst. 2005. A Tropical Garden Flora. Plants Cultivated in the Hawaiian Islands and Other Tropical Places. Bishop Museum Press, Honolulu, HI. 908 pages

6.07

"Seedlings should be potted up into individual containers during their second year and can be planted into the garden or permanent pots in their third year. Flowering can be expected from their third or fourth year"

South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/

7.01

Plants are not necessarily grown in proximity to heavily trafficked areas.

 

7.02

"African lillies are important and abundant ornamentals in Hawaii and the visual effect of a bed in peak blooming is striking. They are popular as massed bedding plants or ground covers and in mixed flower home gardens."

Staples, G.W. and D. R. Herbst. 2005. A Tropical Garden Flora. Plants Cultivated in the Hawaiian Islands and Other Tropical Places. Bishop Museum Press, Honolulu, HI. 908 pages

7.03

Not cultivated alongside produce

 

7.04

Yes, based on seed morphology: "Fruit a 3-angled capsule. Seeds numerous, flat, black, winged."

Staples, G.W. and D. R. Herbst. 2005. A Tropical Garden Flora. Plants Cultivated in the Hawaiian Islands and Other Tropical Places. Bishop Museum Press, Honolulu, HI. 908 pages

7.05

(1)"Dispersal The underground structure forms large continually extending clumps, and seed may wash down waterways. This plant is also frequently dumped on bushland edges." (2)"Seeds blows short distances, fall down banks and are also carried in flowing water. Seed and root fragments are also spread in contaminated soil, dumped vegetation and deliberate planting. Commonly found in gardens, roadsides and banks."

(1)Weeds of Blue Mountain Bushland, Australia. Accessed. 2008.http://www.weedsbluemountains.org.au/weeds_gallery_a-z_common.asp (2)Weedbusters Weed Information New Zealand. Accessed 2008. http://weedbusters.co.nz/weed_info/weed_list.asp

7.06

Unlikely to be eaten by birds, based on fruit and seed morphology "Fruit a 3-angled capsule. Seeds numerous, flat, black, winged."

Staples, G.W. and D. R. Herbst. 2005. A Tropical Garden Flora. Plants Cultivated in the Hawaiian Islands and Other Tropical Places. Bishop Museum Press, Honolulu, HI. 908 pages

7.07

No means of external attchment present

 

7.08

No evidence

8.01

Unlikely, based on plant size and seed morphology

 

8.02

Unknown "Seed can be sown fresh, in late summer - autumn, but in cold climates it can be kept refrigerated (not frozen) and sown in spring. It must be kept in the refrigerator or it will perish. Seed should be sown in deep (10 cm) trays, in a mixture of equal parts river sand and fine compost, and kept semi-shaded and moist. Seed germinates readily within six to eight weeks."

South African National Biodiversity Institute (SANBI). Webpage: PlantZAfrica. Acessed 2008. http://www.plantzafrica.com/

8.03

"Cut the flower heads before the seeds form, while they are still green and sappy. Dig out clumps with a mattock. Try to get most of the roots. Pull seedlings by hand from moist soil when very small. Does not respond well to herbicide, but can be treated by cut and paint: crown, and apply herbicide instantly, before sap bubbles out. Follow-up weeding of seedlings and shoots from rhizomes will be necessary."

CRC for Australian Weed Management. Webpage: Weeds Image Gallery. Accesse 2008. http://www.weeds.crc.org.au/main/image_gallery_page1.html

8.04

(1)"This plant is fire-retardant" (2)"Plants flower more freely in nature in the year following a bush fire"

(1)Whitinger, D. Website: Dave's Garden. Accessed 2008. http://davesgarden.com/ (2)Webpage: Plants for A Future: Edible, Medicinal ans Useful Plants for a Healthier World. Accessed 2008. http://www.pfaf.org/index.php

8.05

Unknown


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