Pittosporum undulatum_Zoya Akulova
Photo by Zoya Akulova

Pittosporum undulatum Risk Assessment

Common names: Victorian box

Pittosporum undulatum -- California

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Evaluation Summary
Summary: 
General Evaluation Information
Date of Evaluation: 
June 16, 2016
Evaluation Time (hrs): 
2 Hours
Evaluation Status: 
Completed
Plant Information
Plant Material: 
If the plant is a cultivar, and if the cultivar's behavior differs from its parent's (behavior), explain how: 
Regional Information
Region Name: 
Climate Matching Map
These maps were built using a toolkit created in collaboration between GreenInfo Network, PlantRight, Cal-IPC, and Agricultural Sustainability Institute at UC Davis.
Climate Matching Maps PDF: 
AttachmentSize
PDF icon PRE_California_Matching_Results_1.pdf571.24 KB
Invasive History and Climate Matching
1. Has the species (or cultivar or variety, if applicable; applies to subsequent "species" questions) become naturalized where it is not native?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
Naturalized in the Azores, Madeira Islands, South Africa, Australia, New Zealand, California, Hawaii, the West Indies (USDA GRIN). Presumably the naturalized Australian populations are the ones in West Australia and South Australia, as the others are in states listed as the native range by USDA. Calflora has >300 records in 17 counties in California. The note sent to the Cal-IPC watchlist for this species said that populations are small and it is more problematic along the northern California coast.
Reference(s): 
2. Is the species (or cultivar or variety) noted as being naturalized in the US or world in a similar climate?
Yes or No: 
Yes
Points: 
2
Confidence Level: 
Very High
Answer / Justification: 
Of the locations listed in Q1, the Azores, Madeira Islands, South Africa, and Australia (West and South) are similar to California's climate. Calflora has >300 records in 17 counties in California. The note sent to the Cal-IPC watchlist for this species said that populations are small and it is more problematic along the northern California coast.
Reference(s): 
3. Is the species (or cultivar or variety) noted as being invasive in the U.S. or world?
Yes or No: 
Yes
Points: 
2
Confidence Level: 
Very High
Answer / Justification: 
Listed as a noxious weed by the state of Hawaii (USDA PLANTS). Weber 2003 lists as invasive in Hawaii, New Zealand, South Africa, Mexico, the Azores, part of Australia, and the Caribbean, with invaded habitats including forests, grasslands, riparian areas, coastal dunes, and scrub.
Reference(s): 
4. Is the species (or cultivar or variety) noted as being invasive in the US or world in a similar climate?
Yes or No: 
Yes
Points: 
3
Confidence Level: 
Very High
Answer / Justification: 
Of the areas listed by Weber 2003, New Zealand, South Africa, Mexico, the Azores, and part of Australia match California's climate. This species colonizes forest gaps and eliminates native vegetation by shading it out. Seedlings form a dense ground cover. The nutrient-rich litter increases soil fertility. It displaces native laurel forests in the Azores and resprouts vigorously after damage.
Reference(s): 
5. Are other species of the same genus (or closely related genera) invasive in a similar climate?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Medium
Answer / Justification: 
Pittosporum viridiflorum has naturalized in Hawaii and P. tenuifolium has naturalized in Australia and California (GISD). Several other species have naturalized in California (DiTomaso and Healy) but I do not have information on invasive impacts for any of these species. Rejmanek lists P. pentandrum as invasive in the Pacific Islands and P. tobira as invasive in France. Locations in France are similar to California (GBIF). A web search of invasive Pittosporums brought up mostly references to P. undulatum. Florida IFAS lists P. tobira as "potentially invasive."
Reference(s): 
6. Is the species (or cultivar or variety) found predominately in a climate matching the region of concern?
Yes or No: 
Yes
Points: 
2
Confidence Level: 
High
Answer / Justification: 
Naturalized in the Azores, Madeira Islands, South Africa, Australia, New Zealand, California, Hawaii, the West Indies (USDA GRIN). Native to the coastal belts and mountains of southeastern Australia (GISD), which are similar to California (Australian Herbarium). GBIF shows some locations in southern Europe and South America in addition to what's listed by USDA. Except for South America, Hawaii, and the West Indies, the locations where it grows are mostly in areas similar to California. Answering yes.
Reference(s): 
Impact on Native Plants and Animals
7. Does this plant displace native plants and dominate (overtop or smother) the plant community in areas where it has established?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
This species colonizes forest gaps and eliminates native vegetation by shading it out. Seedlings form a dense ground cover. The nutrient-rich litter increases soil fertility. It displaces native laurel forests in the Azores, forming monospecific stands, and resprouts vigorously after damage (Weber 2003). Seedling densities can reach 5000 per m2 (GISD).
Reference(s): 
8. Is the plant noted as promoting fire and/or changing fire regimes?
Yes or No: 
No
Points: 
0
Confidence Level: 
High
Answer / Justification: 
References did not mention any connection to fire for this species.
Reference(s): 
9. Is the plant a health risk to humans or animals/fish? Has the species been noted as impacting grazing systems?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Medium
Answer / Justification: 
Produces sapponins, which are not very toxic to humans but can be toxic to fish and have been used as fish-killing chemicals (GISD, quoting Plants for a Future). As this species can grow in riparian vegetation, it is possible these could fall into the stream but the reference does not specify which part of the tree contains the chemicals. Answering with medium confidence based on lack of details or specific examples.
Reference(s): 
10. Does the plant produce impenetrable thickets, blocking or slowing movement of animals, livestock, or humans?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
High
Answer / Justification: 
Weber describes it as having low and dense canopies, thick enough to shade out native vegetation. It is a bushy tree. Based on this description and the fact that it can form monospecific stands, it seems likely to create impenetrable thickets.
Reference(s): 
Reproductive Strategies
11. Does this species (or cultivar or variety) reproduce and spread vegetatively?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
According to Sunset, roots are strong and become invasive with age. Roots resprout vigorously after damage (Weber 2003), which matches the criteria for root sprouts in this question.
Reference(s): 
12. If naturally detached fragments from this plant are capable of producing new plants, is this a common method of reproduction for the plant?
Yes or No: 
No
Points: 
0
Confidence Level: 
Very Low
Answer / Justification: 
No information, although some species of trees can root from pieces.
Reference(s): 
13. Does the species (or cultivar or variety) commonly produce viable seed?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
Pittosporum species produce conspicuous fruits that are the size of peas (Sunset). Fruits contain 12-22 red brown to black seeds (Weber 2003).
Reference(s): 
14. Does this plant produce copious viable seeds each year (> 1000)?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Medium
Answer / Justification: 
Fruits produce 12-22 seeds each. Weber describes it as producing large quantities of seeds. Producing 1000 viable seeds would require 83 fruits with 12 seeds each (assuming 100% viability) or about the same number of fruits with 22 seeds and 50% viability. Given the size of the tree, this seems possible.
Reference(s): 
15. Is there significant germination (>25%) of seeds the next growing season, with no requirement of an infrequent environmental condition for seeds to germinate (i.e. fire) or long dormancy period?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Medium
Answer / Justification: 
Seedlings form a dense ground cover. The species rapidly colonizes forest gaps. Given this description, it does not sound like any special conditions are requires.
Reference(s): 
16. Does this plant produce viable seed within the first three years (for an herbaceous species) to five years (for a woody species) after germination?
Yes or No: 
Points: 
Confidence Level: 
Answer / Justification: 
Could not find information.
Reference(s): 
17. Does this plant continuously produce seed for >3 months each year or does seed production occur more than once a year?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Medium
Answer / Justification: 
Calflora/ the Jepson Manual lists the bloom time for California as November through July. Given this long period, production of seed for more than three months seems possible.
Reference(s): 
Dispersal
18. Are the plant’s propagules frequently dispersed long distance (>100 m) by mammals or birds or via domestic animals?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
Sticky seeds are dispersed by birds and mammals.
Reference(s): 
19. Are the plant’s propagules frequently dispersed long distance (>100 m) by wind or water?
Yes or No: 
No
Points: 
0
Confidence Level: 
High
Answer / Justification: 
Birds and mammals are described as the main source of dispersal.
Reference(s): 
20. Are the plant’s propagules frequently dispersed via contaminated seed (agriculture or wildflower packets), equipment, vehicles, boats or clothing/shoes?
Yes or No: 
No
Points: 
0
Confidence Level: 
High
Answer / Justification: 
Birds and mammals are described as the main source of dispersal.
Reference(s): 
Evaluation Notes

USDA GRIN: https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?id=28757

Calflora: http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=6548

GBIF: http://www.gbif.org/species/2986239

Global Invasive Species Database: http://www.iucngisd.org/gisd/species.php?sc=344

Reviewed by Tim Hyland, California State Parks.

JJM added notes from Plant List Committee conf call in 2015 to determine if we should add Victorian Box.  Randy Baldwin, San Marcos Growers, and others agreed that the suitable range for invasion was narrow, and the most dense population had not moved beyond its area in over 150 years.  Deeemed a lower priority plant among the invasive risks.

 

Total PRE Score

  • < 13 : accept (low risk of invasiveness)
  • 13 - 15 : evaluate further
  • > 15 : reject (high risk of invasiveness)

PRE Score: 
20
Number of questions answered: 
19
Screener Confidence (%): 
80.0
PRE Content Access and Privacy
Evaluation visibility: 
Public - accessible to all site users

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