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

Hypericum canariense; Canary Island St. Johnswort

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

n

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

n

2.05

Does the species have a history of repeated introductions outside its natural range? y=-2

?=-1, n=0

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

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

y

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

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

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

2

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

7.06

Propagules bird dispersed

y=1, n=-1

n

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

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

n

Total score:

9

Source

Notes

1.01

no evidence

1.02

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

"Although the plant has features desirable to horticulturists and is thought to have escaped from cultivation (CDFA 2001), it is currently not widely grown as a garden or landscape plant. A web search in November 2001 revealed that it is kept at the Los Angeles Arboretum and that seeds are offered for sale on the internet (Platt 2001), but on the whole the plant does not seem to be widely offered at wholesale or specialty nurseries in North America. "

1.03

no evidence

2.01

(1)Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002) (2)http://www.biology.ucsc.edu/people/parker/hypericum/biology.htm

((1)Native Range: H. canariense is native to the Canary Islands, where it is often located in xerophytic scrub or forested zones, from 150 to 800 meters in elevation. It can be very common locally (Bramwell & Bramwell 1974). (2)found in dry scrub and laurel forests between 150-800m in elevation [Mediterranean]

2.02

2.03

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

Native Range: H. canariense is native to the Canary Islands, where it is often located in xerophytic scrub or forested zones, from 150 to 800 meters in elevation. It can be very common locally (Bramwell & Bramwell 1974).

2.04

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

Native Range: H. canariense is native to the Canary Islands, where it is often located in xerophytic scrub or forested zones, from 150 to 800 meters in elevation. It can be very common locally (Bramwell & Bramwell 1974).

2.05

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

[examples below are small populations; not broadly introduced to these areas] Santa Barbara, CA
H. canariense made its way to North America (and presumably other parts of the world) as a relatively rare horticultural offering. It is currently displayed at both the Los Angeles County Arboretum and the Missouri Botanical Gardens, but it does not appear to be offered for sale within the United States at this time. It was first reported in the wild in the Santa Barbara, CA area (Munz 1968), where it appeared to be escaping from gardens (Smith 1976). I have looked for it in the Santa Barbara region this year, but I have not found it there. It is also not known to anyone I've spoken to at the universities and botanical gardens in the area. The rapid urbanization and expansion of Santa Barbara may have out-paced this particular H. canariense invasion.
Munz, P. (1968). Supplement to A California Flora. Berkeley, University of California Press.
Smith, C. (1976). A flora of the Santa Barbara region, California: an an

3.01

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

Range As An Invader:
In North America, H. canariense occurs as an invader in Hawaii and in California (USDA-NRCS 2001). Previous reports from California list this species as being present only in San Diego and Santa Barbara counties in southern California (CalFlora 2001). The Jepson Manual: Higher Plants of California (Hickman 1993) lists the species as uncommon in disturbed places below 100 m in the South Coast subregion of the state. In San Diego, H. canariense has escaped cultivation as an ornamental near the Point Loma military cemetery (M. Kelly, pers. comm.).
In San Mateo County in northern California, H. canariense currently covers approximately 25 to 40 hectares (62-99 acres) near Gazo Creek (J. Wade, pers. comm.). John Wade of the Pescadero Conservation Alliance reports that there are several populations of H. canariense along the coast, and that they are all rapidly expanding in range.

3.02

not answered since Yes for Envirnmental weed; no evidence of being a garden or amenity weed

3.03

no evidence

3.04

(1) Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)
(2) Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

(1) "Hypericum canariense has recently been observed invading natural areas in San Mateo, Santa Barbara and San Diego counties in California. It is thought to have escaped from cultivation, as it has traits desirable to horticulturists (i.e. attractive, ornamental foliage and large, bright orange flowers). Native to the Canary Islands, it has been found growing in the wild in disturbed places, coastal sage scrub, and in grassland habitats up to 100 meters in elevation in coastal areas of California. H. canariense has the potential to extend its range inland from its present coastal distribution. "
(2) Eradication Efforts: H. canariense will resprout if cut to the ground, and there is no primary stem suitable for a weed wrench. Thus far, eradication has been attempted via herbicide sprays. In Hawai'i, control of H.canariense is fairly easy with the herbicide triclopyr ester (brand name Garlon 4). It is susceptible to foliar treatment, but seasonally may not have enough leaf surface available for uptake. It s

3.05

Bacon, P., P.J. Terry, N. Waltham, & P.Castro S. (1997) An Electronic Atlas of World Weed and Invasive Plants. Version 1.0, 1997. A database based on the original work "A Geographical Atlas of World Weeds" by Holm et al 1979.

H. androsaemum was reported as a principal weed in New Zealand; H. elodes was reported as a common weed in Portugal; H. ereetum, H. itxum were reported as a common weed in Japan; H. erispum was repoterd as a principal weed in Tinisia , and common weed in Lebanon; H. japonicum was reported as a common weed inTaiwan; H. maeulatum was reported as a common weed in Finland; H. perforatum was reported as a serious weed in Australia and United States; as a principal weed in Hungary, Italy, Sweden, and Turkey; as a common weed in Canada, Iran, Poland, South Africa and Russian Federation; H. quadrangulum was reported as a common weed in Russian Federation; H. triquetrifolium was reported as a common weed in Lebanon.

4.01

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

"Hypericum canariense is a shrub in the Hypericaceae (formerly Clusiaceae) - St. Johnswort family. H. canariense can grow up to 5 meters tall and has simple, opposite leaves that are oblong-lanceolate, with tapered bases. They range in size from 2 to 7 cm long. The yellow-orange flowers are large and showy with petals (12 to 15 mm in size) and stamens that persist after flowering. The sepals are ovate with pointed tips and have ciliate hairs along their margins. The fruits are leathery capsules that open at maturity (Hickman, J.C. (ed.). 1993. The Jepson Manual: Higher Plants of California. University of California Press, Berkeley.).

4.02

no evidence

4.03

no evidence

4.04

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

"This species does not seem to be widely used by deer. Insect herbivores do occur in the native range. "

4.05

no evidence

4.06

no evidence

4.07

no evidence

4.08

http://tncweeds.ucdavis.edu/alert/alrthype.html

dense growth in dry envirnonments, carries few leaves

4.09

http://tncweeds.ucdavis.edu/alert/alrthype.html

"H. canariense is native to the Canary Islands, where it is often located in xerophytic scrub or forested zones" ; "The Jepson Manual: Higher Plants of California (Hickman 1993) lists the species as uncommon in disturbed places below 100 m in the South Coast subregion of the state. In San Diego, H. canariense has escaped cultivation as an ornamental near the Point Loma military cemetery (M. Kelly, pers. comm.). "
"John Wade of the Pescadero Conservation Alliance reports that there are several populations of H. canariense along the coast"
[It seems to invade only disturbed or dry sites that have sufficient light.]

4.1

no evidence

4.11

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

"Hypericum canariense is a shrub in the Hypericaceae (formerly Clusiaceae) - St. Johnswort family. H. canariense can grow up to 5 meters tall and has simple, opposite leaves that are oblong-lanceolate, with tapered bases. They range in size from 2 to 7 cm long. The yellow-orange flowers are large and showy with petals (12 to 15 mm in size) and stamens that persist after flowering. The sepals are ovate with pointed tips and have ciliate hairs along their margins. The fruits are leathery capsules that open at maturity (Hickman, J.C. (ed.). 1993. The Jepson Manual: Higher Plants of California. University of California Press, Berkeley.).

4.12

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

Impacts: The overall impacts of this new invader are unknown, but H. canariense appears to outcompete and exclude nearly all other vegetation once it has invaded. In coastal California areas that have become infested, H. canariense can comprise up to 90 to 100% of the vegetation cover, and it outcompetes and excludes both the native scrub vegetation (Baccharis spp., Toxicodendron diversilobum) as well as other non-native vegetation such as jubatagrass (Cortaderia jubata). The only native plants that persist after H. canariense invasions are trees that are over 1.5 m tall (J. Wade, personal communication). In favorable conditions, infestations of H. canariense can spread at a rate of up to 45-90 meters per year.

5.01

terrestrial

5.02

Clusiaceae, shrub

5.03

no evidence

5.04

shrub

6.01

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

"H. canariense is native to the Canary Islands, where it is often located in xerophytic scrub or forested zones, from 150 to 800 meters in elevation. It can be very common locally (Bramwell, D. and Z. Bramwell. 1974. Wildflowers of the Canary Islands. Stanley Thornes, Ltd., London.). "

6.02

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

Reproduction: From April to June, H. canariense produces showy terminal clusters of orange-yellow flowers. The flowers are approximately 1.5cm across, with five sepals, five petals, three stigmas (sometimes four), and many anthers. The dry, capsule fruits mature and dehisce from July through August, releasing hundreds of tiny seeds (1mm in length). Plants are likely to take two to three years from seed to flowering adult.

6.03

no evidence

6.04

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

"My initial investigations indicate that these plants are indeed self-pollinating"

6.05

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

"My initial investigations indicate that these plants are indeed self-pollinating"

6.06

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

6.07

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

"Plants are likely to take two to three years from seed to flowering adult."

7.01

no evidence

7.02

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

"Although the plant has features desirable to horticulturists and is thought to have escaped from cultivation (CDFA 2001), it is currently not widely grown as a garden or landscape plant. A web search in November 2001 revealed that it is kept at the Los Angeles Arboretum and that seeds are offered for sale on the internet (Platt 2001), but on the whole the plant does not seem to be widely offered at wholesale or specialty nurseries in North America. "

7.03

no evidence

7.04

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

The dry, capsule fruits mature and dehisce from July through August, releasing hundreds of tiny seeds (1mm in length) having no particular adptations for dispersal.

7.05

Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)

Reproduction and Methods of Dispersal: H. canariense produces large amounts of viable seed. Many seedlings have been found just downslope of mature shrubs in San Diego County (M. Kelly, pers. comm.). [pictures show plants along drainage canal in S. California]

7.06

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

"The dry, capsule fruits mature and dehisce from July through August, releasing hundreds of tiny seeds (1mm in length)." [fruit a dry capsule]

7.07

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

The dry, capsule fruits mature and dehisce from July through August, releasing hundreds of tiny seeds (1mm in length) having no particular adptations for dispersal.

7.08

no evidence

8.01

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

"The dry, capsule fruits mature and dehisce from July through August, releasing hundreds of tiny seeds (1mm in length)."

8.02

http://www.biology.ucsc.edu/people/parker/hypericum/biology.htm

Water is suffcient to break seed dormancy,

8.03

(1) Wildland Invasive Species Team, The Nature Conservancy. Weed Alert: Hypericum canariense L. (Canary Island St. Johnswort). Webpage available at: <http://tncweeds.ucdavis.edu/alert/alrthype.html>(23 October 2002)
(2) Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

(1) Control: Mike Kelly (personal communication) has been successful controlling H. canariense by using the cut-stump herbicide application method. He first cut the stems with a chainsaw, then applied the herbicide glyphosate (brand name RoundUp) at full strength to the cut-stump. Mike suspects that a less-concentrated solution of herbicide might also be effective, but has not tested the efficacy of differing amounts of herbicide on H. canariense control.
(2) Thus far, eradication has been attempted via herbicide sprays. In Hawai'i, control of H.canariense is fairly easy with the herbicide triclopyr ester (brand name Garlon 4). It is susceptible to foliar treatment, but seasonally may not have enough leaf surface available for uptake. It seems, at least in Hawai'i, that it is quite susceptible to basal bark treatments any time of year (20% Garlon 4 in oil carrier).

8.04

Katrina Dlugosch (dlugosch@biology.ucsc.edu). Hypericum canariense (Canary Island St. Johnswort). Webpage available at <http://www.biology.ucsc.edu/people/parker/hypericum/>(23 October 2002)

"H. canariense will resprout if cut to the ground, and there is no primary stem suitable for a weed wrench. "

8.05

no evidence