Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service

Information on Risk Assessments
Original risk assessment

Osteospermum fruticosum (Dimorphotheca fruticosa, trailing african daisy, shrubby daisly bush, freeway daisy)

Answer

1.01

Is the species highly domesticated?

y=-3, n=0

n

1.02

Has the species become naturalized where grown?

y=-1, n=-1

y

1.03

Does the species have weedy races?

y=-1, n=-1

n

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

n

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

n

2.05

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

?=-1, n=0

n

3.01

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

y

3.02

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

n=0

n

3.03

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

n=0

n

3.04

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

n=0

3.05

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

n=0

y

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

n

4.03

Parasitic

y=1, n=0

n

4.04

Unpalatable to grazing animals

y=1, n=-1

y

4.05

Toxic to animals

y=1, n=0

n

4.06

Host for recognized pests and pathogens

y=1, n=0

y

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

4.09

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

y=1, n=0

n

4.1

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

y=1, n=0

n

4.11

Climbing or smothering growth habit

y=1, n=0

n

4.12

Forms dense thickets

y=1, n=0

n

5.01

Aquatic

y=5, n=0

n

5.02

Grass

y=1, n=0

n

5.03

Nitrogen fixing woody plant

y=1, n=0

n

5.04

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

y=1, n=0

n

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

6.02

Produces viable seed.

y=1, n=-1

y

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

6.05

Requires specialist pollinators

y=-1, n=0

n

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

y

6.07

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

See left

1

7.01

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

y=1, n=-1

n

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

7.04

Propagules adapted to wind dispersal

y=1, n=-1

n

7.05

Propagules water dispersed

y=1, n=-1

n

7.06

Propagules bird dispersed

y=1, n=-1

n

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

7.08

Propagules survive passage through the gut

y=1, n=-1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

n

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

8.04

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

y=1, n=-1

y

8.05

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

y=-1, n=1

Total score:

3

Source

Notes

1.01

No evidence

1.02

(1) on the list of naturalized plant of California
(2) on the list of "Common Weeds of New Zealand."

(1) http://ucjeps.berkeley.edu/interchange/I_status_2.html
(2) http://www.rnzih.org.nz/pages/weednameslist.htm

1.03

No evidence

2.01

Origin: Southern Africa [mediterranean coastal plant rather than tropical/subtropical?]

http://www.desert-tropicals.com/Plants/Asteraceae/Osteospermum_fruticosum.html

2.02

'The popularity of Osteospermum fruticosum boomed in the late 1960's, when this perennial with cheerful white flowers was planted along freeways all over low-elevation California.'

http://shop.store.yahoo.com/classicnursery91335/osfrutafdais1.html

2.03

(1)USDA: 9,10 (all zones when grown as annual)
(2)Grows upto 200 m altitude. (3)Coastal cliffs, waste places

(1)http://www.desert-tropicals.com/Plants/Asteraceae/Osteospermum_fruticosum.html (2)http://www.osteospermum.com/ (3)Webb et al. 1988. Flora of New Zealand Volume IV. Botany Division DISR, Christchurch, New Zealand.

2.04

No evidence

2.05

(1) Introduced to the U.S. [No evidence of other introductions] (2) Hawaii, (3) California, (4) New Zealand

http://plants.usda.gov/cgi_bin/plant_profile.cgi?symbol=OSFR4
(2) Nishimoto, R. K.; Rauch, F. D.; Parvin, P. E. (1977) Evaluation of preemergence herbicides for weed control in Research Report, Hawaii Agricultural Experiment Station, 1977, No.226, 12 pp., 7 ref.
(3) Gill, H. S. (1975) An unusual outbreak of Whetzelinia rot on African daisies in California. Plant Disease Reporter, 1975, Vol.59, No.1, pp.82-83, 2 ref.
(4) http://www.rnzih.org.nz/pages/weednameslist.htm

3.01

(1) on the list of naturalized plant of California
(2) on the list of "Common Weeds of New Zealand."

(1) http://ucjeps.berkeley.edu/interchange/I_status_2.html
(2) http://www.rnzih.org.nz/pages/weednameslist.htm

3.02

No evidence

3.03

No evidence

3.04

(1)According to an April, 1997 Interior Department news release, in 1989, a single clump of a South African annual composite (Osteospermum fruticosum) was found on Santa Cruz Island off the Ventura County coast. The entire population was successfully removed. (2)may have invasive [California; not on CalEPPC lists] (3)on the list of "Common Weeds of New Zealand." [no details available] (4)In New Zealand - "established locally in the wilde as a garden escape" [implies not a major pest]

(1)http://www.albrightseed.com/greenaliens.htm (2)http://www.ucfpl.ucop.edu/I-Zone/XIV/vegetati.htm (3)http://www.rnzih.org.nz/pages/weednameslist.htm (4)Webb et al. 1988. Flora of New Zealand Volume IV. Botany Division DISR, Christchurch, New Zealand.

3.05

http://tncweeds.ucdavis.edu/esadocs.html

4.01

No evidence

Horticopia A to Z. CD-ROM database.

4.02

No evidence

4.03

No evidence

4.04

Deer resistant

http://www.woodsidefire.org/pdfs/demogarden.pdf

4.05

No evidence

4.06

(1)lettuce mosaic potyvirus (LMV) [<http://www.inra.fr/Internet/Produits/HYP3/pathogene/6letmov.htm> Contamination of the fields occurs from weed hosts (21 species belonging to 9 families : mainly Compositae). Very severe mosaic followed by necrosis on a lettuce leaf infectedby LMV] (2)AB: Decaying roots and cankered crowns of Osteospermum fruticosum and O. ecklonis yielded an isolate tentatively identified as a virulent A1 str. of P. cryptogea.

(1)ET: Freeway daisy (Osteospermum fruticosum ) as host for lettuce mosaic virus. AU: Opgenorth, D. C.; White, J. B.; Oliver, B.; Greathead, A. S. SO: Plant Disease, 1991, Vol.75, No.7, p.751 (2)ET: Phytophthora disease of African daisies in California. AU: Gill, H. S.; Ribeiro, O. K.; Klure, L. J.; Zentmyer, G. A. SO: Phytophthora Newsletter, 1976, No.4., p.33

4.07

on the list of "Recommended Plants for Homes of Allergic People"

http://www.peds.arizona.edu/allergyimmunology/southwest/lowallrgylflowers.htm

4.08

fire retardant plants

http://www.ucfpl.ucop.edu/I-Zone/XIV/vegetati.htm

4.09

(1) Sun Exposure: Full sun (2)prefers full sun

(1)http://www.desert-tropicals.com/Plants/Asteraceae/Osteospermum_fruticosum.html (2)http://www.hortpix.com/pc3000.htm

4.1

Soil Condition Loamy, neutral, tolerates salt, drought tolerant

Horticopia A to Z. CD-ROM database.

4.11

groundcover

Horticopia A to Z. CD-ROM database.

4.12

No evidence

5.01

Herb/Forb

http://plants.usda.gov/cgi_bin/plant_profile.cgi?symbol=OSFR4

5.02

Asteraceae

5.03

No evidence

5.04

No evidence

6.01

No evidence

6.02

'It is not recommended to collect seed from Osteospermums. Most Osteospermums are hybrids and the resulting seedlings will not come true to the original plant. This means that the resulting plants will never be identical and can therefore not be given the same name as the original plant. Osteospermum hybrids must be propagated by cuttings.'

http://www.osteospermum.com/

6.03

(1) 'An epiphytotic of W. (Sclerotinia) sclerotiorum on Osteospermum fruticosum, O. ecklonis and their hybrids (Snow White and Burgundy Mounds) planted along highways in S. Calif. is reported.' (2) 'It is not recommended to collect seed from Osteospermums. Most Osteospermums are hybrids and the resulting seedlings will not come true to the original plant. This means that the resulting plants will never be identical and can therefore not be given the same name as the original plant. Osteospermum hybrids must be propagated by cuttings.' [don't know if hybrids are natural]

(1) An unusual outbreak of Whetzelinia rot on African daisies in California. AU: Gill, H. S. SO: Plant Disease Reporter, 1975, Vol.59, No.1, pp.82-83, 2 ref. (2)http://www.osteospermum.com/

6.04

No evidence

6.05

no evidence based on flower morphology [typical Asteraceae, insect pollinated]

Horticopia A to Z. CD-ROM database.

6.06

(1)Propagation: Cuttings (2)spreads 2-3' a year, 6-12' high; roots as it goes (3)Spreads rapidly by trailing, rooting branches.

(1)http://www.desert-tropicals.com/Plants/Asteraceae/Osteospermum_fruticosum.html (2)http://ag.arizona.edu/classes/lar520/unit9/ostefrut.htm (3)http://shop.store.yahoo.com/classicnursery91335/osfrutafdais1.html

6.07

can be grown as an annual

http://growers.harrisseeds.com/cart/browse.asp?subcat=182

7.01

No evidence that the seeds have any means of attachment.

7.02

An ornamental plant.

Horticopia A to Z. CD-ROM database.

7.03

No evidence

7.04

Achenes obovoid, glabrous, 3-angled [no description of a pappus or other dispersal adaptation]

Webb et al. 1988. Flora of New Zealand Volume IV. Botany Division DISR, Christchurch, New Zealand.

7.05

a coastal plant [doubful if seeds are ocean dispersed]

7.06

pests: birds will eat seeds and seedlings

Horticopia A to Z. CD-ROM database.

7.07

no description of barbs for attachment

Webb et al. 1988. Flora of New Zealand Volume IV. Botany Division DISR, Christchurch, New Zealand.

7.08

pests: birds will eat seeds and seedlings [Birds regarded as pests for eating seeds - not dispersers]

Horticopia A to Z. CD-ROM database.

8.01

(1) 80 Seeds Per Gram [not tiny seeds] (2)few achenes present in the wild collections

(1)http://www.seeds-by-size.co.uk/mfl-8-98.htm (2)Webb et al. 1988. Flora of New Zealand Volume IV. Botany Division DISR, Christchurch, New Zealand.

8.02

No evidence regarding seedbank.

8.03

(1)'Herbicides were evaluated in rooted and non-rooted cuttings of Hotentot-fig (Carpobrotus edulis), small iceplant (Delasperma alba), yellow trailing iceplant (Malephora luteolus) and trailing African daisy
(Osteospermum fruticosum). Napropamide at 4 and 8 lb/acre, nitrofen at 4 lb/acre, oryzalin at 2 and 4 lb/acre and prodiamine at 2 and 4 lb/acre were applied the day after planting prior to a light sprinkler irrigation. Oryzalin and prodiamine resulted in better overall weed control and more rapid growth of the ground covers than napropamide and nitrofen. Rooted cuttings of all 4 species and non-rooted cuttings of Hotentot-fig showed satisfactory tolerance to all the herbicides. Non-rooted cuttings of small iceplant and yellow trailing iceplant grew less than rooted cuttings and non-rooted cuttings of trailing African daisy established poorly in all the treatments. In a separate study, rooted cuttings of Japanese honeysuckle (Lonicera japonica) showed satisfactory tolerance to the 4 herbicides

(1)ET: Update on ground cover weed control.
AU: Humphrey, W. A. SO: Proceedings of the 31st Annual California Weed Conference., 1979, pp.100-102 (2)ET: Evaluation of preemergence herbicides for weed control in ground covers in Hawaii. AU: Nishimoto, R. K.; Rauch, F. D.; Parvin, P. E. SO: Research Report, Hawaii Agricultural Experiment Station, 1977, No.226, 12 pp., 7 ref. (3) ET: Growth retardants for control of ground covers.
AU: Criley, R. A. SO: Departmental Paper, Hawaii Agricultural Experiment Station, 1976, No.46, 8 pp., 2 ref.

8.04

(1) 'Tip-pinching young plants induces bushiness; cutting back old, sprawling branches to young side branches keeps plants neat, often induces repeat bloom. (2) 'AB: Eight species of groundcovers commonly used in the southwestern United States were subjected to renovation by mowing during a 2-year study: red apple, coyote bush, pink iceplant, trailing lantana, prostrate myoporum, trailing African daisy, dwarf rosemary and garden verbena. Plant response was evaluated monthly in terms of total height, thickness of thatch, density, and overall appearance. Six species responded favorably to mowing at a height of 10 cm (4 in) in that thatch and height were significantly reduced for up to several months with only a brief loss in aesthetic quality. Coyote bush, trailing lantana, prostrate myoporum and garden verbena responded well to March mowings, while pink iceplant and trailing African daisy responded well to June mowings. In the two species that did not respond favorably (red apple and dwarf rosemary),

(1) http://shop.store.yahoo.com/classicnursery91335/osfrutafdais1.html (2)TI: Responses of eight groundcover species to renovation by mowing. AU: Hodel-D-R; Pittenger-D-R SO: Journal-of-Environmental-Horticulture. 1994; 12 (1) 4-7..

8.05

Don’t know