Pacific Island Ecosystems at Risk (PIER)


Bauhinia variegata


RISK ASSESSMENT RESULTS: High risk, score: 9


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

Bauhinia variegata (purple orchid tree, mountain ebony)

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

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

y

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

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

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

n

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

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

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

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

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

n

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

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:

9

Supporting data:

Notes

Source

1.01

No evidence

1.02

(1)A problem species in Florida. Reported weedy in gardens in Hawai‘I. (2)Noted as a common escape, abundantly invading disturbed areas in particular. Naturalized in the Caribbean and elsewhere in the Neotropics as well. Spreading from sites where previously planted in Big Cypress National Preserve. Found in 10 conservation areas in Dade County; displacing native vegetation in hammock margins and occasionally in globally imperiled pine rocklands. Reported now from natural areas in four counties: Pinellas, Lee, Dade, and Palm Beach, including the Loxahatchee National Wildlife Refuge and Everglades National Park.

(1)http://www.hear.org/pier/bavar.htm. (2)http://216.239.53.100/search?q=cache:-a8bchEIHREC:www.fleppc.org/pdf/Bauhinia%2520variegata.pdf+Bauhinia+variegata&hl=en&ie=UTF-8

1.03

No evidence

2.01

(1)B. vareigata is naturally found in the sub-Himalayan tract and outer hills and valleys from the river Indus in Pakistan eastwards to Assam and Myanmar, ascending to altitudes of 1500 to 1830 m (2)native to northern India, Viet Nam and southeastern China.

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.floridata.com/ref/B/bauh_var.cfm

2.02

Widely planted in the tropics and warm regions of the world, including the southern margin of the United States from Florida to California; probably also naturalized in Louisiana and perhaps Texas.

http://216.239.53.100/search?q=cache:-a8bchEIHREC:www.fleppc.org/pdf/Bauhinia%2520variegata.pdf+Bauhinia+variegata&hl=en&ie=UTF-8

2.03

(1)USDA: 10 (2)Hardiness Range: 9B - 11
(3) Climate
B. variegata is a species of tropical and subtropical climates with hot dry summers and mild winters. In its natural habitat the absolute maximum shade temperature varies from 37.5 to 47.5C, the absolute minimum from 0 to 17C with optimum rainfall of 760-1900 mm (Troup, 1983). It avoids dry tracts with rainfall less than 500 mm.
Descriptors
- Altitude range: 0 - 1830 m
- Mean annual rainfall: 500 - 2550 mm
- Rainfall regime: summer; winter; bimodal
- Dry season duration: 3 - 4 months
- Mean annual temperature: 0 - 48C
- Mean maximum temperature of hottest month: 30 - 42C
- Mean minimum temperature of coldest month: 7 - 14C
- Absolute minimum temperature: 0 - 17C (4)not tolerant of salty conditions, USDA Zones 9 - 11, Orchid tree is a subtropical plant that usually recovers from brief freezes (5)Drought tolerance: high

(1)http://www.desert-tropicals.com/Plants/Fabaceae/Bauhinia_variegata.html (2)http://www.hortpix.com/pc660.htm
(3) CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (4)http://www.floridata.com/ref/B/bauh_var.cfm (5)http://edis.ifas.ufl.edu/ST092

2.04

B. vareigata is naturally found in the sub-Himalayan tract and outer hills and valleys from the river Indus in Pakistan eastwards to Assam and Myanmar, ascending to altitudes of 1500 to 1830 m

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

2.05

Planted in several countries.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

3.01 (1)A problem species in Florida. Reported weedy in gardens in Hawai‘I. (2)Noted as a common escape, abundantly invading disturbed areas in particular. Naturalized in the Caribbean and elsewhere in the Neotropics as well. Spreading from sites where previously planted in Big Cypress National Preserve. Found in 10 conservation areas in Dade County; displacing native vegetation in hammock margins and occasionally in globally imperiled pine rocklands. Reported now from natural areas in four counties: Pinellas, Lee, Dade, and Palm Beach, including the Loxahatchee National Wildlife Refuge and Everglades National Park. (1)http://www.hear.org/pier/bavar.htm. (2)http://216.239.53.100/search?q=cache:-a8bchEIHREC:www.fleppc.org/pdf/Bauhinia%2520variegata.pdf+Bauhinia+variegata&hl=en&ie=UTF-8

3.02

A problem species in Florida. Reported weedy in gardens in Hawai‘i

http://www.hear.org/pier/bavar.htm

3.03

No evidence

3.04

(1)Category 1 invasive species. This category identifies "invasive exotics that are altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives"Noted as a common escape, abundantly invading disturbed areas in particular. Naturalized in the Caribbean and elsewhere in the Neotropics as well. Spreading from sites where previously planted in Big Cypress National Preserve. Found in 10 conservation areas in Dade County; displacing native vegetation in hammock margins and occasionally in globally imperiled pine rocklands. Reported now from natural areas in four counties: Pinellas, Lee, Dade, and Palm Beach, including the Loxahatchee National Wildlife Refuge and Everglades National Park. (2)Category 3 invader in South Africa [lowest rating] (3)Caution: This species has been identified as a potential weed in the Maranoa (Ma) district [Australia]

(1)http://216.239.53.100/search?q=cache:-a8bchEIHREC:www.fleppc.org/pdf/Bauhinia%2520variegata.pdf+Bauhinia+variegata&hl=en&ie=UTF-8 (2)http://www.weedwarriors.co.za/Pests2.html (3)http://www.forests.qld.gov.au/qts/treetext.html

3.05

B. purpurea is invasive in Florida

http://www.fnps.org/chapters/dade/pubs/PlantsToAvoid.html

4.01

No evidence

http://www.hear.org/pier/bavar.htm

4.02

(1) "Fourteen crop and tree species, and wild bushes were tested for allelopathy towards Parthenium hysterophorus: chickpea cv. C-235, Trifolium alexandrinum cv. Mescavi, Trigonella foenum graecum cv. Kasuri, Acacia nilotica, Albizia procera, Bauhinia variegata, Delonix regia, Moringa indica, Parkinsonia aculeata, Pithecellobium dulce, Prosopis cineraria, Tamarindus indica, Cassia occidentalis and Tephrosia purpurea. Aqueous leachates (100%) from leaves of all tested species, except that of Pithecellobium dulce, decreased seed germination and vigour index of Parthenium hysterophorus. "
(2) "In general bark extract of K. calycina and G. oppositifolia significantly reduced germination of all crops, followed by leaf and bark extracts of B. variegata. Radicle growth of all crops except finger millet was suppressed by bark extracts, and leaf extracts reduced radicle growth of all crops. Soyabeans were the most susceptible and barnyard millet most resistant to the toxic action of the tree extracts."
(3) "it has bee

(1) Dhawan, S. R.; Poonam Dhawan; Gupta, S. K. (2001) Allelopathic potential of leguminous plant species towards Parthenium hysterophorus L. (1) - effect of aqueous foliar leachates. Legume Research, 2001, Vol. 24, No. 4, pp. 256-259, 24 ref.
(2) Kaletha, M. S.; Bhatt, B. P.; Todaria, N. P. (1996) Tree-crop interactions in traditional agroforestry systems of Garhwal Himalaya. 1. Phytotoxic effects of farm trees on food crops. Allelopathy Journal, 1996, Vol. 3, No. 2, pp. 247-250, 12 ref.
(3) CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

4.03

4.04

"The leaves, shoots and pods of B. variegata are used as fodder for livestock, including sheep, goats and cattle. High quality fodder makes it eminently suitable for silvopastoral systems, its nutritious leaves becoming available when other forage is scarce. "

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

4.05

"The leaves, shoots and pods of B. variegata are used as fodder for livestock, including sheep, goats and cattle. High quality fodder makes it eminently suitable for silvopastoral systems, its nutritious leaves becoming available when other forage is scarce. "

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

4.06

There are no records of highly important pests and diseases for B. vareigata (Hocking, 1993). However, it is susceptible to damage by some insects, rodents, and epiphytic and parasitic organisms. Termites can be a threat to nursery seedlings and young saplings, particularly if the plants have been weakened by drought.
Pests recorded: Insect pests:
Caryedon serratus
Indarbela quadrinotata
Psylla simlae

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

4.07

"B. variegata leaves, fruits, pods and exudates are edible by humans and are consumed as a vegetable as well as made into pickles and chutneys"

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

4.08

(1)deciduous to semi- deciduous tree. [single trunk tree with leathery leaves]

(1)http://www.cuyamaca.net/oh170/Characteristic%20Pages/Bauhinia%20variegata.asp

4.09

(1)Sun Exposure: Full sun to light shade. (2)Grows best in full sun or partial shade. (3) prefers partial shade or partial sun to full sun. (4)Exposure: [ x ] Full Sun (5) " It is a gregarious species which is shade tolerant"

(1)http://www.desert-tropicals.com/Plants/Fabaceae/Bauhinia_variegata.html (2)http://216.239.53.100/search?q=cache:-a8bchEIHREC:www.fleppc.org/pdf/Bauhinia%2520variegata.pdf+Bauhinia+variegata&hl=en&ie=UTF-8 (3)http://www.hortpix.com/pc660.htm (4)http://www.cuyamaca.net/oh170/Characteristic%20Pages/Bauhinia%20variegata.asp
(5) CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

4.1

(1)Tolerates a wide range of well-drained soils but prefers acidic soils. (2)Orchid trees do best in acidic soil and suffer under limey conditions (3)clay; sand; loam; acidic; slightly alkaline; well-drained

http://216.239.53.100/search?q=cache:-a8bchEIHREC:www.fleppc.org/pdf/Bauhinia%2520variegata.pdf+Bauhinia+variegata&hl=en&ie=UTF-8 (2)http://www.floridata.com/ref/B/bauh_var.cfm (3)http://edis.ifas.ufl.edu/ST092

4.11

Probably not - not a vine.

4.12

It is a gregarious species [but no evidence of thickets]

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

5.01

5.02

20-40' tall and 10-20' wide, briefly deciduous leaves

5.03

(1) "B. variegata is a non-nitrogen fixing species "
(2) Twenty-seven tree species, whose seeds were obtained from the Plant Introduction Unit of the Forest Research Institute, Dehra Dun, India, were grown first in sand (to height 10-12 cm), and then in pot culture in soil/farmyard manure (3:1) for 2-3 months. Records were made of nodulation in each species, and healthy plants were selected for determination of the nitrogen fixing activity of their isolated nodules. Sixteen of the species tested (12 Mimosoideae and 4 Papilionoideae) formed nodules which exhibited nitrogen fixing activity; data are tabulated on nodule fresh weight, number and acetylene reduction activity for each. The 16 nitrogen fixing species were Acacia albida, A. benthemii [A. benthamii], A. catechu, A. lenticularis, A. nilotica, Albizia lebbeck [A. lebbek], A. procera, Leucaena leucocephala, Mimosa pudica (field collected), Enterolobium timbouva [E. contortisiliquum], Prosopis cineraria, P. chilensis, Dalbergia sissoo, Derris robusta, Pon

(1) CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

(2) Pokhriyal, T. C.; Bhandari, H. C. S.; Negi, D. S.; Chaukiyal, S. P.; Gupta, B. B. (1990) Identification of some fast growing leguminous tree species for nitrogen fixation studies. Indian Forester, 1990, Vol. 116, No. 6, pp. 504-507, 8 ref.

 

5.04

tree

6.01

The large pink, purple or white flowers appear from February to April, In the northern parts of India and Pakistan the pods form rapidly, ripening in May and June

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

6.02

Seeds germinate readily and show a high germination

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

6.03

Hong Kong orchid tree (Bauhinia X blakeana is a sterile hybrid between (probably) B. variegata and B. purpurea

http://www.floridata.com/ref/B/bauh_var.cfm

6.04

The species is mainly cross-pollinated (10-21.6%) in nature with a small amount of selfing (Luna, 1996).

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

6.05

The large amount of pollen production, floral polymorphism (shape, size and colour) and fragrance enhance cross-pollination and foraging activities of various pollinators, including bees.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

6.06

root suckers

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

6.07

Bauhinias species grow easily from seeds and bloom within 3 to 4 years

http://www.wpsm.net/Bauhinia.pdf

7.01

Probably not - the propagules do not have any means of attachment.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

7.02

The tree is very handsome when in flower and is widely planted as an ornamental

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

7.03

Probably not - 'The seeds are 1.3-1.8 x 1.3-1.7 cm and nearly circular, flat and brown with a somewhat coriaceous testa.'

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

7.04

They contain 10-15 seeds and mainly dehisce on the trees, scattering the seed.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

7.05

They contain 10-15 seeds and mainly dehisce on the trees, scattering the seed.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

7.06

(1)Fruit characteristics: does not attract wildlife (2)attracts birds [conflicting information; birds could be pollinators]

(1)http://edis.ifas.ufl.edu/ST092 (20http://www.mckeowninc.com/plants.html?pid=bauvarca

7.07

They contain 10-15 seeds and mainly dehisce on the trees, scattering the seed.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

7.08

no evidence of consumption

8.01

Probably not - seeds relatively large. The seeds are 1.3-1.8 x 1.3-1.7 cm and nearly circular, flat and brown with a somewhat coriaceous testa.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

8.02

(1)Seeds germinate readily and show a high germination (up to 95% when fresh), which is retained to some extent for at least one year. Seed stored in dry conditions in sealed containers gives good results after two years
(2) A fast-growing tree with seeds that remain viable for more than a year.

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://216.239.53.100/search?q=cache:-a8bchEIHREC:www.fleppc.org/pdf/Bauhinia%2520variegata.pdf+Bauhinia+variegata&hl=en&ie=UTF-8

8.03

Basal bark application of 10% Garlon 4 or application of 50% Garlon 3A to cut stump.

http://edis.ifas.ufl.edu/WG209

8.04

Ability to sucker; suited for coppicing; suited for pollarding

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

8.05

Don’t know


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