Pacific Island Ecosystems at Risk (PIER)


Tillandsia usneoides


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

Tillandsia usneoides (Renealmia usneoides, Strepsia usneoides, Spanish moss, old man's beard, grandfather’s whiskers, air plant)

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

n

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

3.04

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

n=0

n

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

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

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

y

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

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

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

y

7.04

Propagules adapted to wind dispersal

y=1, n=-1

y

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

y

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

n

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:

Source

Notes

1.01

No evidence

1.02

"Spanish Moss-naturalized, Tillandsia usneoides " [naturalized in Bermuda]

http://coexploration.org/projects/heidi/nonnative.htm

1.03

No evidence

2.01

(1)North American native. Native Habitat: Southeastern United States to Argentina. (2)Moist tropics and subtropics. (3)Native range: Americas from southeastern US to Chile and Argentina.

(1)Horticopia A to Z. CD-ROM database. (2)AND (3)http://www.hear.org/pier/tiusn.htm

2.02

2.03

(1)Hardiness Range 9A to 11 (2)Climate group- sub-tropical. (3)High humidity from fog between 600-700 m on La Campana provides conditions for luxuriant growth of cryptogamic epiphytes and bromeliads, e.g. Tillandsia usneoides.[moist habitats] (3)requiring only warm, humid air [for growth]. (4)it prefers damp,shaded forests.(5)It only grows in swampy damp areas [naturally] (6)chiefly in coastal areas 0-400 m

(1)Horticopia A to Z. CD-ROM database. (2)Horticopia Plant Master 5.5. CD-ROM database. (3)http://www.nmnh.si.edu/botany/projects/cpd/sa/sa44.htm (4)http://www.plantoftheweek.org/week056.shtml (4)http://www.adventureoutpost.net/Tours4New.htm (5)http://plantsdatabase.com/go/2060.html (6)Adams, C.D. Flowerinig Plants of Jamaica. University of the West Indies, Mona

2.04

North American native. Native Habitat: Southeastern United States to Argentina.

Horticopia A to Z. CD-ROM database.

2.05

Introduced to several Pacific Islands. [also widely introduced via packing material, seat cushionns, etc]

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

3.01

"Spanish Moss-naturalized, Tillandsia usneoides " [naturalized in Bermuda]

http://coexploration.org/projects/heidi/nonnative.htm

3.02

No evidence

3.03

'Spanish moss can become so thick that it shades the leaves of its host, or, when heavy with rainwater, breaks a branch. Although a tree might be weakened, it would not likely be killed by Spanish moss. However, it is considered a pest in pecan orchards.'[native to Florida]

http://www.floridata.com/ref/t/till_usn.cfm

3.04

No evidence

3.05

(1) AB: "In parts of Venezuela the epiphyte Tillandsia recurvata is sufficiently abundant to kill whole trees or their main branches. Its mode of propagation is described. In the laboratory detached plants were readily killed by submergence in various herbicidal solutions. "
(2) AB: "In field trials in south-west Texas in 1970-71, good control of Tillandsia recurvata on the evergreen Quercus virginiana was obtained by spring with Cu(OH)2 (Kocide 101) at 4-8 lb/100 gal water."
[T. recurvata was considered as a weed and subjected to control]

(1) Cardenas, C. H. (1971) Observations on Tillandsia recurvata and its control by means of herbicides. Revista de la Facultad de Agronomia, Universidad Central de Venezuela, 1971, Vol.6, No.2, pp.43-72
(2) Johnson, J. D.; Halliwell, R. S. (1970) Compounds for the control of ball moss. Plant Disease Reporter, 1973, Vol.57, No.1, pp.81-83, 1 ref.

4.01

No evidence of any such structures.

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

4.02

No evidence

4.03

'Spanish moss is not a parasite. That is, it does not take nutrients or water from the host tree on which it lives.

http://www.floridata.com/ref/t/till_usn.cfm

4.04

Don’t know [an epiphyte that usually grows beyond the reach of browsing animals ]

4.05

No evidence

4.06

No evidence regarding any pests or pathogens associated with this species.

4.07

No evidence

4.08

Hygroscopic leaves, Evergreen perennial [but dead or dried plants hanging in trees could be fire hazard?]

Horticopia A to Z. CD-ROM database.

4.09

(1)Exposure Partial shade or partial sun to full sun (2)Full sun.
(3)Light: Full sunlight to partial shade. (4)It will not grow in full afternoon sun, prefers morning sun and some partical shade (5)It can also be grown indoors in bright light.

(1)Horticopia A to Z. CD-ROM database. (2)Horticopia Plant Master 5.5. CD-ROM database. (3)http://www.floridata.com/ref/t/till_usn.cfm (4)http://plantsdatabase.com/go/2060.html (4)http://hgic.clemson.edu/factsheets/HGIC1501.htm

4.1

(1)Root form: Epiphytic. Soil Condition Neutral, tolerates salt. (2)The stems and leaves are slender and curly, and covered with tiny silvery-gray scales that catch water and nutrients (in dust particles) from the air. [epiphytic]

(1)Horticopia A to Z. CD-ROM database. (2)http://www.floridata.com/ref/t/till_usn.cfm

4.11

(1) 'Spanish moss can become so thick that it shades the leaves of its host, or, when heavy with rainwater, breaks a branch. Although a tree might be weakened, it would not likely be killed by Spanish moss. However, it is considered a pest in pecan orchards.' (2)In some cases the moss will get extremely heavy and could break a branch, this normally occurs if the tree is in decline for some other reason. What happens is, as the canopy foliage decreases more light reaches the Spanish moss and it flourishes. The Spanish moss is not the cause of the problem it just benefits from the decline of the tree.

(1)http://www.floridata.com/ref/t/till_usn.cfm (2)http://www.herbnews.org/aflash/plantsanimals.htm

4.12

an epiphyte.

5.01

Terrestrial

Horticopia A to Z. CD-ROM database.

5.02

Bromeliad

Horticopia A to Z. CD-ROM database.

5.03

Bromeliad

Horticopia A to Z. CD-ROM database.

5.04

(1)Root Form: epiphytic (2)Pendent, much-branched, usually rootless epiphyte to 8 m long.

(1)Horticopia A to Z. CD-ROM database. (2)http://www.hear.org/pier/tiusn.htm

6.01

The flowers are inconspicuous, pale green or blue, and fragrant at night.

http://www.floridata.com/ref/t/till_usn.cfm

6.02

The seeds lodge in the cracks of rough-barked live oaks, where a seedling can fasten temporary roots to keep it in place.'

http://www.wcsscience.com/spanish/moss.html

6.03

no evidence

6.04

no evidence

6.05

no evidence [possibly yes; a relative of pineapple]

6.06

(1)Propagation: Seeds and pieces of the shoots. (2)It's primary means of reproduction is vegetative -

(1)http://www.hear.org/pier/tiusn.htm (2)http://www.adventureoutpost.net/Tours4New.htm

6.07

Don’t know

7.01

no evidence

7.02

(1)Suitable for dried flowers (2)It is often used in decorative floral arrangements and handicrafts...Spanish moss is sometimes hung on fences or wires to create privacy screens.  

(1)Horticopia A to Z. CD-ROM database. (2)http://www.floridata.com/ref/t/till_usn.cfm

7.03

Probably yes - 'Spanish moss produces tiny seeds that sail on the wind and stick fast to tree branches. Birds and the wind carry fragments of the plant to new locations, probably the commonest means of propagation'. [packing material]

http://www.floridata.com/ref/t/till_usn.cfm

7.04

'Spanish moss produces tiny seeds that sail on the wind and stick fast to tree branches. Birds and the wind carry fragments of the plant to new locations, probably the commonest means of propagation.'

http://www.floridata.com/ref/t/till_usn.cfm

7.05

no evidence

7.06

'Spanish moss produces tiny seeds that sail on the wind and stick fast to tree branches. Birds and the wind carry fragments of the plant to new locations, probably the commonest means of propagation.'

http://www.floridata.com/ref/t/till_usn.cfm

7.07

'Spanish moss produces tiny seeds that sail on the wind and stick fast to tree branches. Birds and the wind carry fragments of the plant to new locations, probably the commonest means of propagation.'

http://www.floridata.com/ref/t/till_usn.cfm

7.08

Don’t know

8.01

(1)Capsule to 25 mm long. Seeds 2-3 mm long; appendage to 25 mm long, white (2)Spanish moss rarely blooms in cultivation. (3)It's primary means of reproduction is vegetative

(1)http://www.hear.org/pier/tiusn.htm (2)http://www.plantoftheweek.org/week056.shtml (3)http://www.adventureoutpost.net/Tours4New.htm

8.02

Probably not - an epiphyte.

8.03

When a pest control company comes in to remove moss [Tillandsia] , they spray a very common fungicide that also will kill bromeliads like Spanish moss. In most cases removal of Spanish moss is not necessary.

http://www.herbnews.org/aflash/plantsanimals.htm

8.04

spread by fragments, wind

http://www.floridata.com/ref/t/till_usn.cfm

8.05

Don’t know


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


[ Return to PIER homepage ] [Risk assessment page]


This page updated 6 March 2005