Pacific Island Ecosystems at Risk (PIER)


Rubus argutus


RISK ASSESSMENT RESULTS: High risk, score: 21.5


Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.

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

Rubus argutus Link ; Rubus betulifolius, Rubus louisianus, Rubus penetrans, sawtooth blackberry, prickly Florida blackberry

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

y

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

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

3.02

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

n=0

y

3.03

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

n=0

3.04

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

n=0

y

3.05

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

n=0

y

4.01

Produces spines, thorns or burrs

y=1, n=0

y

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

n

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

4.09

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

y=1, n=0

y

4.1

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

y=1, n=0

y

4.11

Climbing or smothering growth habit

y=1, n=0

n

4.12

Forms dense thickets

y=1, n=0

y

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

y

6.04

Self-compatible or apomictic

y=1, n=-1

y

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

y

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

y

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

y

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

y

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

8.02

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

y=1, n=-1

y

8.03

Well controlled by herbicides

y=-1, n=1

y

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:

21.5

Supporting data:

Notes

Source

1.01

no evidence

1.02

"It was introduced to Hawaii in 1894 (Neal 1965), probably for horticultural reasons"; "It is now naturalized on all major islands"

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

1.03

The cultivated blackberries grown in Australia are all complex hybrids, mostly derived from successive generations of controlled crosses. They may be grouped according to derivation as (i) mainly Rubus ursinus germplasm; (ii) derivatives of R. ulmifolius [R. inermis] crossed with R. argutus and R. alleghaniensis, and (iii) derivatives of R. alleghaniensis. Cultivated blackberries do not manifest weedy behaviour or represent a threat to Australian ecosystems, either through naturalization or hybridization. Hybridization between crop Rubus and weedy Rubus is slight, and produces hybrids less adapted to survival as weeds than seedlings of weedy Rubus. [wild populations are weedy]

McGregor, G. (1998) Relationships between weedy and commercially grown Rubus species. Editor: Groves, R. H. Williams, J. Corey, S. Plant Protection Quarterly, 1998, Vol. 13, No. 4, pp. 157-159, 5 ref.

2.01

Native range: Central and eastern United States

2.02

(1)Seed - requires stratification and is best sown in early autumn in a cold frame. [mainly warm temperate but also occurs in most of Florida]

http://www.gardenbed.com/r/3330.cfm

2.03

(1)"It occurs in wet to mesic habitats mostly between 300 m and 2,500 m elevation (Gerrish pers. comm.). It is best developed from 1,000 m to 2,000 m elevation in mesic to moderately wet, relatively open, and disturbed habitats. " (2)Distribution: Oklahoma, Alabama, Georgia, Kentucky, and Virginia. Habitat: upland prairies and dry woodlands. (3)"Native habitats include wet or swampy woodlands, often in standing water, streambanks, soreline thickets, but also in dry places"

(1)http://tncweeds.ucdavis.edu/esadocs/documnts/rubuarg.html (2)http://www.biosurvey.ou.edu/shrub/rubu-arg.htm (3)Weber, E. 2003. Invasive plants of the world. CABI Publishing. Cambridge.

2.04

"It was introduced to Hawaii in 1894 (Neal 1965), probably for horticultural reasons "; "It is now naturalized on all major islands"

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

2.05

(1) Chile, (2) "It was introduced to Hawaii in 1894 (Neal 1965), probably for horticultural reasons" (3)Occurs on North Island of New Zealand

(1) Medel S., F. Vargas V., H. (1981) Phenology and adaptability of bush and cane fruits in the Lake region of Chile. (Foreign Title: Fenologia y adaptibilidad de los arbustos frutales en la Region de Los Lagos.) Agro Sur, 1981, Vol. 9, No. 1, pp. 59-64, 19 ref. (2) http://tncweeds.ucdavis.edu/esadocs/documnts/rubuarg.html (3)http://www.weeds.crc.org.au/documents/blackberry_wshop.pdf

3.01

"In Hawai'i, an extremely serious weed naturalized in a variety of disturbed habitats, including mesic to wet forest and subalpine grassland, 200-2,300 m "

http://www.hear.org/pier/species/rubus_argutus.htm

3.02

(1) "A 3 year study in Florida from 1989 to 1991 investigated highbush blackberry (Rubus argutus) control in bahiagrass roadside turf (Paspalum notatum)" (2)A native with white blooms in spring, edible berries, but too aggressive and thorny for trailside (in North Carolina) [amenity weed]

(1)McCarty, L. B. Colvin, D. L. Higgins, J. M. (1996) Highbush blackberry (Rubus argutus) control in bahiagrass (Paspalum notatum). Weed Technology, 1996, Vol. 10, No. 4, pp. 754-761, 4 ref (2)http://www.ellerbecreek.org/stewards0001.htm

3.03

"these species are categorized as competitors to pine during stand regeneration" [weed of pine forestry plantations?]

Cain, M. D. Shelton, M. G. (2003) Fire effects on germination of seeds from Rhus and Rubus: competitors to pine during natural regeneration. New Forests, 2003, Vol. 26, No. 1, pp. 51-64, 32 ref.

3.04

(1) an extremely serious weed naturalized in a variety of disturbed habitats, including mesic to wet forest and subalpine grassland, 200-2,300 m " (2)The major threats to Alsinidendron obovatum are competition from the aggressive nonnative plant species...Rubus argutus (3)Alsinidendron lychnoides (kuawawaenohu) -- The major threats to this species are competition from the aggressive nonnative plant species Rubus argutus (prickly Florida blackberry) (4)This thorny scrambler is a noxious weed which rapidly invades disturbed areas between 1,000-2,300 m.It forms impenetrable thickets (5)Hawaii Noxious weed (6)Exocarpos luteolus -- Aggressive alien taxa degrading this plant's habitat include Acacia mearnsii (black wattle), Corynocarpus laevigatus (karakanut), Myrica faya (firetree), and Rubus argutus

(1)Wagner, W.L., D.R. Herbst and S.H. Sohmer. 1999. Manual of the flowering plants of Hawai'i. University of Hawai'i Press, Honolulu. pp. 1107, 1890. (2)http://a257.g.akamaitech.net/7/257/2422/14mar20010800/edocket.access.gpo.gov/2003/03-11156.htm (3)http://a257.g.akamaitech.net/7/257/2422/14mar20010800/edocket.access.gpo.gov/2003/03-2840.htm (4)http://www.botany.hawaii.edu/faculty/carr/rub_arg.htm (5)http://www.hawaii.edu/ehso/bio/weedlist.pdf

3.05

Rubus anglocandicans was suggested as a "weed of national significance "

Evans, K. J. Weber, H. E. (2003) Rubus anglocandicans (Rosaceae) is the most widespread taxon of European blackberry in Australia. Australian Systematic Botany, 2003, Vol. 16, No. 4, pp. 527-537, 29 ref.

4.01

" covered with stout, straight or hooked prickles up to 6 (-8) mm lon (stem)"; "lower surface usually soft pilose and midrib usually with small prickles (leaf)"

4.02

no evidence

4.03

no evidence

4.04

Twenty-five samples of blackberry shoots were taken from each of two sites, one grazed by cattle and one in a nearby ungrazed location.

http://www.dc.peachnet.edu/~jaliff/gajsci591.htm [THE EFFECTS OF HERBIVORY ON MECHANICAL DEFENSE IN BLACKBERRIES, RUBUS ARGUTUS, Haley Caldwell*, Lisa Bradford, Chandra Leigh, Jeremy Pirkle and Mark Davis, North Georgia College & State University, Dahlonega, GA 30597.]

4.05

no evidence

4.06

While examining common blackberry stems and apple fruit in North Carolina for fungal colonies, thalli and pycnidia atypical of the apple soot blotch pathogen Gloeodes pomigena were observed. Specimens on brambles were collected in Apr. and May 1993 and were identified as G. polystigmatis. Colonies characteristic of G. polystigmatis were observed on apple fruit during the summer of 1993 but pycnidia were rarely found on them. However, a small barren circular area within the thallus remained as evidence of the prior presence of pycnidia. The fungus was readily cultured on potato-dextrose agar. This is the first report of G. polystigmatis in North America.
[a specific rust fungus infecting apple]

Johnson, E. M. Sutton, T. B. (1994) First report of Geastrumia polystigmatis on apple and common blackberry in North America. Plant Disease, 1994, Vol. 78, No. 12, pp. 1219, 1 ref.

4.07

no evidence

4.08

thickets could potentially be a fire hazard in drier areas but no direct evidence

4.09

(1)"Blackberry is moderately shade tolerant, and grows best in forest gaps or under a sparse canopy. It can be shaded out or severely suppressed by deep shade." (2)sun or semi-shade

(1)http://tncweeds.ucdavis.edu/esadocs/documnts/rubuarg.html (2)http://www.gardenbed.com/r/3330.cfm

4.1

Adapted to Coarse Textured Soils: Yes
Adapted to Fine Textured Soils: Yes
Adapted to Medium Textured Soils: Yes

USDA, NRCS. 2004. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

4.11

"Stems usually erect to arching in open areas and arching to trailing or decumbent in shaded areas" [thicket forming]

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

4.12

"Forms impenetrable thickets."

http://www.hear.org/pier/species/rubus_argutus.htm

5.01

5.02

Erect or becoming arching shrubs, Rosaceae

5.03

no evidence

5.04

shrub

6.01

"In Hawai'i, an extremely serious weed naturalized in a variety of disturbed habitats, including mesic to wet forest and subalpine grassland, 200-2,300 m "

http://www.hear.org/pier/species/rubus_argutus.htm

6.02

"Propagation: Seed"

http://www.hear.org/pier/species/rubus_argutus.htm

6.03

(1)Field identification: sharp-toothed dewberry is closely related to R. ostryifolius. Rubus is a complex genus. Species are difficult to identify due to frequent hybridization and introgression.

(1)http://www.biosurvey.ou.edu/shrub/rubu-arg.htm

6.04

'Most commercial cultivars of blackberries, black raspberries, and raspberries areself-fruitful and do not require pollinizers.'

http://66.102.7.104/search?q=cache:Pa3xDpzRM0UJ:www.uga.edu/fruit/black%26rasp.pdf+Rubus+argutus+self+incompatible&hl=en

6.05

listed on the table of "Plants for Year-Round Bee Forage"

http://www.ces.uga.edu/pubcd/b1106-w.html

6.06

"Blackberry can form clonal thickets by root sprouting, although aerial shoots may occasionally root when in contact with soil "

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

6.07

Aboveground stems can reach 3 feet (1 m) in height in less than 2 months [thornless variety of R. argutus]

http://www.fs.fed.us/database/feis/plants/shrub/rubcan/all.html

7.01

occurs in dry or moist thickets [in moist areas, small seeds may be transported in mud along hiking trails]

http://www.gardenbed.com/r/3330.cfm

7.02

(1) introduced to Chile as fruit crop, (2) "It was introduced to Hawaii in 1894 (Neal 1965), probably for horticultural reasons"

(1) Medel S., F. Vargas V., H. (1981) Phenology and adaptability of bush and cane fruits in the Lake region of Chile. (Foreign Title: Fenologia y adaptibilidad de los arbustos frutales en la Region de Los Lagos.) Agro Sur, 1981, Vol. 9, No. 1, pp. 59-64, 19 ref. (2) http://tncweeds.ucdavis.edu/esadocs/documnts/rubuarg.html

7.03

suggested as a contaminant in a soil of transplanting pine seedlings

Shelton, M. G. Cain, M. D. (2002) Potential carry-over of seeds from 11 common shrub and vine competitors of loblolly and shortleaf pines. Canadian Journal of Forest Research, 2002, Vol. 32, No. 3, pp. 412-419, 30 ref.

7.04

"spread by birds and other animals"

http://www.hear.org/pier/species/rubus_argutus.htm

7.05

"spread by birds and other animals"

http://www.hear.org/pier/species/rubus_argutus.htm

7.06

"spread by birds and other animals"

http://www.hear.org/pier/species/rubus_argutus.htm

7.07

"spread by birds and other animals"

http://www.hear.org/pier/species/rubus_argutus.htm

7.08

"Seed, spread by birds and other animals"

http://www.hear.org/pier/species/rubus_argutus.htm

8.01

(1)"Fruit an aggregation of drupelets, 6-15 mm long (0.25-0.65 in), oblong, black; nutlets yellow" (2)Based on photograph, each fruit contains roughly 20 drupelets. [might produce 50 fruits per m2? borderline]

(1)http://tncweeds.ucdavis.edu/esadocs/documnts/rubuarg.html (2)http://www.hear.org/pier/images/ruargp11.jpg

8.02

AB: "To evaluate the potential carry-over of the seeds from 11 shrub and vine competitors of these two important southern pines, we designed packets so that fruits could be deposited on the forest floor and subsequently extracted over a 3-year period...blackberry (Rubus argutus Link) were moderate in viability (7-19%) after the third year of field storage"

Shelton, M. G. & Cain, M. D. (2002) Potential carry-over of seeds from 11 common shrub and vine competitors of loblolly and shortleaf pines. Canadian Journal of Forest Research, 2002, Vol. 32, No. 3, pp. 412-419, 30 ref.

8.03

Control of blackberry by cut stem application of undiluted Roundup or Rodeo may be less time consuming and more practical than manual control when canes are scattered and soil in not deep and loose. Canes should be cut as close to the soil line as possible. Lower concentrations than those used by Smith may be effective.
Foliar applications of 2% Roundup or Escort at 28 g/l are probably the most effective herbicidal means of control known. However, both of these are very damaging to non-target vegetation in foliar treatments.

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

8.04

Can be encouraged or rejuvenated by … mowing, light burning, or deep cultivation; Burning typically stimulates sprouting [thornless variety of R. argutus]

http://www.fs.fed.us/database/feis/plants/shrub/rubcan/all.html

8.05

"Biological control has been partly effective (Nagata and Markin 1986). Five insects were released 1963-1969 as biocontrol agents. Three of these became established, and were causing extensive damage by the mid-1960's (Nagata and Markin 1986). Nagata and Markin (1986) found substantial populations of these species and concluded that they were having some effect in controlling populations of blackberry, particularly the Schreckensteinia festaliella, a leaf skelentonizer, and Croesia zimmermani, a leaf roller. Markin (pers. comm.) is currently attempting to determine why released insects are not more effective, and feels that parasites on the biocontrol insects may limit their effectiveness as biocontrol agents. "

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


Need more info? Have questions? Comments? Information to contribute? Contact PIER!


[ Return to PIER homepage ] [Risk assessment page]


This page new 10 February 2005