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

Rhodomyrtus tomentosa (Myrtus tomentosa; rose myrtle)

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

2

2.02

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

2

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

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

y

3.05

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

n=0

n

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

4.05

Toxic to animals

y=1, n=0

n

4.06

Host for recognized pests and pathogens

y=1, n=0

n

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

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

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

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

n

6.07

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

See left

3

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

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

y

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

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:

8

Source

Notes

1.01

no evidence

1.02

Campbell, C. W. (1977). Cultivation of tropical fruits of the Myrtaceae in southern Florida. Proceedings of the Tropical Region, American Society for Horticultural Science, 1977, Vol.21, pp.3-7, 5 ref. (p. 6)

"Downy myrtle is an acid-loving plant which will not grow in calcareous soils, but grow well in acid sandy soils of Southern Florida and is naturalized in acid, poorly drained "fllat-woods" area of the lower west coast"

1.03

no evidence

2.01

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 276

It is growing wild and cultivated South East Asia, India, Sri Lanka, and Southern China

2.02

2.03

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 277

var. tomentosa is generally found in harsh environments, up to elevetions of 300m, rarely up to 1300m. On the other hand, var. parviflora occurs in montane woodlands and grassland at altitudes of 1800-2700m.

2.04

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 276

It is growing wild and cultivated South East Asia, India, Sri Lanka, and Southern China

2.05

(1) Turner, I. M.; Ong, B. L.; Tan, H. T. W. (1995). Vegetation analysis, leaf structure and nutrient status of a Malaysian heath community. Biotropica, 1995, Vol.27, No.1, pp.2-12, 41 ref.
(2) Sun, G. C.; Lin, Z. F.(1989). A study of photosynthetic ecophysiology in subtropical monsoon evergreen broadleaved forest in Dinghushan Nature Reserve. Acta Botanica Austro Sinica, 1989, No.5, pp.109-116, 16 ref.
(3) Campbell, C. W. (1977). Cultivation of tropical fruits of the Myrtaceae in southern Florida. Proceedings of the Tropical Region, American Society for Horticultural Science, 1977, Vol.21, pp.3-7, 5 ref.  

(1) Malaysia (2) China (3) Florida; grown widely for horticulture (e.g. Australia)

3.01

Campbell, C. W. (1977). Cultivation of tropical fruits of the Myrtaceae in southern Florida. Proceedings of the Tropical Region, American Society for Horticultural Science, 1977, Vol.21, pp.3-7, 5 ref. (p. 6)

Southern Florida, is naturalized in acid, poorly drained "fllat-woods" area of the lower west coast"

3.02

no evidence

3.03

no evidence

3.04

(1)http://aquat1.ifas.ufl.edu/rhotom.html (2)http://www.botany.hawaii.edu/faculty/cw_smith/rho_tom.htm (3)http://www.eswr.com/f012802b.txt [Federal Register: January 28, 2002 (Volume 67, Number 18)] Page 3939-3988]

(1)Downy rose myrtle (Rhodomyrtus tomentosa), native to Asia, is spreading unchecked in Florida, taking over the understory of native pinelands, and probably altering the natural fire regimes of southern Florida. Introduced as landscaping plants, heavy infestations of downy rose myrtle already occur in several central and southern counties, including Lee, Palm Beach, Broward and Dade Counties, and as far north as Pasco County. It also occurs as an invasive weed in Hawaii. (2)This noxious evergreen shrub rarely grows above 3 m but forms dense thickets. There is a major infestation on Kaua'i, particularly in Kilohana Crater. (3)Cyanea undulata -- The primary threats to this species include competition with the non-native plant species Psidium cattleianum, Melastoma candidum, Rhodomyrtus tomentosa (rose myrtle)

3.05

no evidence

4.01

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 276

4.02

no evidence

4.03

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 276

4.04

no evidence

4.05

no evidence

4.06

4.07

no evidence

4.08

http://aquat1.ifas.ufl.edu/rhotom.html

probably altering the natural fire regimes of southern Florida

4.09

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 277

"Downy myrtle thrives in open, often degraded sandy sites, along the shore and open river banks."

4.1

(1) Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 277 (2) Campbell, C. W. (1977). Cultivation of tropical fruits of the Myrtaceae in southern Florida. Proceedings of the Tropical Region, American Society for Horticultural Science, 1977, Vol.21, pp.3-7, 5 ref. (p. 6)

(1) "Moist somewhat acid oils are preferred; the plant is not well adapted to limestome soils." (2) "Downy myrtle is an acid-loving plant which will not grow in calcareous soils, but grow well in acid sandy soils of Southern Florida and is naturalized in acid, poorly drained "fllat-woods" area of the lower west coast"

4.11

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 276

Evergreen shrub or small tree, up to 4 m tall.

4.12

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 277

"Where it grows, other plants seem not to be able to compete with it, hence almost pure stands exist."

5.01

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 276

Evergreen shrub or small tree, up to 4 m tall.

5.02

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 276

Evergreen shrub or small tree, up to 4 m tall.

5.03

no evidence

5.04

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 276

Evergreen shrub or small tree, up to 4 m tall.

6.01

no evidence

6.02

Campbell, C. W. (1977). Cultivation of tropical fruits of the Myrtaceae in southern Florida. Proceedings of the Tropical Region, American Society for Horticultural Science, 1977, Vol.21, pp.3-7, 5 ref. (p. 6)

"Propagation is by seed"

6.03

no evidence

6.04

6.05

no evidence

6.06

http://aquat1.ifas.ufl.edu/rhotom.html

does not spread vegetatively

6.07

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 277, Dr R. Criley, Dept. of Horticulture, University of Hawaii Manoa

Plants raised from cuttings will bear fruit in about 2 years

7.01

no evidence

7.02

Campbell, C. W. (1977). Cultivation of tropical fruits of the Myrtaceae in southern Florida. Proceedings of the Tropical Region, American Society for Horticultural Science, 1977, Vol.21, pp.3-7, 5 ref. (p. 6)

"Sold in some nurseries and found in many home gardens, this plants deserves to bemore widely planted in areas where soil conditions are suitable."

7.03

no evidence

7.04

no evidence

7.05

no evidence

7.06

Verheij, E.W.M. & R. E. Coronel (eds.). 1991. Edible fruits and nuts. In: Plant Resources of South-East Asia (PROSEA) (Pl Res SEAs)No 2: 276

"Children compete with birds for the sweet, edible fruit."

7.07

no evidence

7.08

bird dispersal

8.01

http://www.daleysfruit.com.au/facber.html

The berries with inconspicuous seeds (like blueberries, dozens of seeds per fruit). Copious fruit production.

8.02

8.03

Motooka, P. 2000. Summary of herbicide trials for pasture, range and non-cropland weed control-1999. Weed Control Feb. 2000 WC-5 published by CTAHR/ University of Hawaii (p.4 table7.)

well-controlled by triclopyr

8.04

http://aquat1.ifas.ufl.edu/rhotom.html

resprouts prolifically after fires.

8.05