Climate Matching Map
| Attachment | Size |
|---|---|
| climatematch-pentaglottis_sempervirens-california-20251101.pdf (1.11 MB) | 1.11 MB |
1. Question 1
Yes
1
Very High
This species' home range is western Europe, excluding the U.K. It is currently found in the U.K., New Zealand, Tasmania and south eastern Australia, and western North America where it is not native.
Rolfe, Jeremy. (2008) 2008. “New Exotic Plant Records and Range Extensions for Naturalised Plants in the Southern North Island”. Wellington. https://bts.nzpcn.org.nz/site/assets/files/22779/wbs51-2008-31-50-exoti….
2. Question 2
Yes
2
High
Climate matching map shows climate overlap with naturalized range in California with current known points in Oregon, Tasmania and New Zealand.
No references cited.
3. Question 3
Yes
2
Medium
Native Plant Society, Emerald Chapter, of Oregon lists as invasive.
Noted as invasive by Botanical Society of Britain and Ireland. Noted as a watch species by the Washington State Noxious Weed Control board. No formal government agencies list the species as invasive, as of this writing.
Noted as invasive by Botanical Society of Britain and Ireland. Noted as a watch species by the Washington State Noxious Weed Control board. No formal government agencies list the species as invasive, as of this writing.
“Oregon Noxious Weeds”. 2019. https://www.invasive.org/species/list.cfm?id=56.
Ireland, Botanical Society of Britain and. 2021. “Distribution Map -Pentaglottis Sempervirens”. https://bsbi.org/maps?taxonid=2cd4p9h.ccv.
Board, Washington State Noxious Weed Control. 2021. “Green Alkanet”. https://www.nwcb.wa.gov/weeds/green-alkanet.
4. Question 4
No
0
Very Low
No reports of this species being invasive in climate areas that match California. It is invasive in the U.K., where climate does not match. There are reports of it spreading, such as in New Zealand, but there doesn't seem to be information describing that spread as invasive (causing damage) and it is spreading in New Zealand where the climate is not a match.
Society, The Royal Horticultural. 2021. “Pentaglottis Sempervirens Green Alkanet”. http://www.rhs.org.uk/Plants/12486/Pentaglottis-sempervirens/Details.
Rolfe, Jeremy. (2008) 2008. “New Exotic Plant Records and Range Extensions for Naturalised Plants in the Southern North Island”. Wellington. https://bts.nzpcn.org.nz/site/assets/files/22779/wbs51-2008-31-50-exoti….
“Pentaglottis Sempervirens (Green Alkanet) Again”. (2013) 2013. https://archive.bsbi.org/BSBINews123.pdf.
Board, Washington State Noxious Weed Control. 2021. “Green Alkanet”. https://www.nwcb.wa.gov/weeds/green-alkanet.
5. Question 5
Yes
1
Medium
Pentaglottis sempervirens is a monotypic genus. Some species in Anchusa are present in the US, including in California, Oregon and Washington. Anchusa officinialis is listed as invasive in Washington. Anchusa azure is listed as invasive in Oregon.
Anchusa should be a closely related genus (Anchusa is a synonym for Pentaglottis and both are in the Boragininae subtribe of Boraginaceae)
Anchusa should be a closely related genus (Anchusa is a synonym for Pentaglottis and both are in the Boragininae subtribe of Boraginaceae)
“Pacific Northwest Noxious Weed Lists”. 2021. http://depts.washington.edu/waipc/pnwnoxiousweedlist.shtml.
6. Question 6
No
0
High
While this species is found throughout the northern Iberian peninsula, where the climate matches that of California, the preponderance of locations where this species is found (western and northern Europe) does not match the climate of California.
No references cited.
7. Question 7
No
0
Medium
There is not enough info that it overtops or dominates vegetation where it has established. It appears to be spreading in the UK where is outcompetes garden vegetation and vegetation in wildlands too. It appears to be spreading in natural areas in Oregon, but not displacing native vegetation
Society, Royal Horticultural. 2021. “Green Alkanet”. Royal Horticultural Society. https://www.rhs.org.uk/advice/profile?PID=1001.
8. Question 8
No
0
Medium
It appears to stay green all year, and grows in wet often forested places, thus the plant should produce limited amounts of dry fuels and the fire risk should be low.
Perrone, Jane. 2020. “Green Alkanet, That Mystery Plant”. https://www.janeperrone.com/blog/greenalkanet.
Board, Washington State Noxious Weed Control. 2021. “Green Alkanet”. https://www.nwcb.wa.gov/weeds/green-alkanet.
9. Question 9
No
0
Low
The leaves are hairy and some gardeners report it causes irritation. Irritation is not enough to justify yes for toxic
Minimal information on effects on livestock grazing. Closely related plants contain alkaloids.
Minimal information on effects on livestock grazing. Closely related plants contain alkaloids.
No references cited.
10. Question 10
No
0
Medium
The plant only grows 2-3 ft. (1 m) tall, it does not grow tall enough to create impenetrable thickets.
No references cited.
11. Question 11
No
0
Medium
The plant has a deep tap root and when severed it can re-sprout, but this is not a form of vegetative reproduction, thus no answer.
Society, The Royal Horticultural. 2021. “Pentaglottis Sempervirens Green Alkanet”. http://www.rhs.org.uk/Plants/12486/Pentaglottis-sempervirens/Details.
12. Question 12
No
0
Medium
Sources do not mention that pieces of tap root commonly are moved around. Tap root fragment seem to be deep and not likely to be transported regularly.
Board, Washington State Noxious Weed Control. 2021. “Green Alkanet”. https://www.nwcb.wa.gov/weeds/green-alkanet.
13. Question 13
Yes
1
Very High
Produces seeds
Board, Washington State Noxious Weed Control. 2021. “Green Alkanet”. https://www.nwcb.wa.gov/weeds/green-alkanet.
14. Question 14
No
0
Very Low
Each flower produces 4 seeds. It is difficult to tell from pictures on the internet if large plants can produce more than 250 flowers per plant. A large plant could be capable of producing over 1,000 seeds, but it is difficult to tell given current resources, unless a picture is found where the flowers can be easily counted on a single plant.
Perrone, Jane. 2020. “Green Alkanet, That Mystery Plant”. https://www.janeperrone.com/blog/greenalkanet.
Board, Washington State Noxious Weed Control. 2021. “Green Alkanet”. https://www.nwcb.wa.gov/weeds/green-alkanet.
15. Question 15
Yes
1
Medium
Gardeners report that it is easy to grow in gardens in the UK. Several gardening resources also show that it easily seeds each subsequent spring and suggest that it self seeds to the point of being a "nuisance". This seems to support that a significant number of seeds germinate each year, however no formal studies have been conducted only anecdotal observations by gardeners.
Society, Royal Horticultural. 2021. “Green Alkanet”. Royal Horticultural Society. https://www.rhs.org.uk/advice/profile?PID=1001.
Future, Plants for a. 2021. “Pentaglottis Sempervirens - (L.)Tausch”. https://pfaf.org/user/Plant.aspx?LatinName=Pentaglottis+sempervirens.
16. Question 16
Yes
1
Medium
Reaches full size in 2 years. Many of the pictures on iNaturalist and gardening websites seem to show that full size plants can flower and thus are likely to produce viable seed. However, there does not seem to be a reliable account of how quickly it sets seed. It seems quite reasonable that it can seed within 3 years based on plant growth. Confidence medium.
Society, Royal Horticultural. 2021. “Green Alkanet”. Royal Horticultural Society. https://www.rhs.org.uk/advice/profile?PID=1001.
Limited, Shoot. 2021. “Shoot Gardening Pentaglottis Sempervirens”. https://www.shootgardening.co.uk/plant/pentaglottis-sempervirens.
17. Question 17
Yes
1
Medium
No published information for California or Western US. Flowers from spring through summer, in U.K. and it produces flowers as it grows. New Zealand Flora shows a blowing period of 4 months. It is difficult to confirm flowering season in North America, however iNaturalist observations from western North America show pictures of flowering plants from April to August.
Board, Washington State Noxious Weed Control. 2021. “Green Alkanet”. https://www.nwcb.wa.gov/weeds/green-alkanet.
Society, Royal Horticultural. 2021. “Green Alkanet”. Royal Horticultural Society. https://www.rhs.org.uk/advice/profile?PID=1001.
Reserach, Land Care. 2021. “New Zealand Flora”. https://www.nzflora.info/factsheet/Taxon/Pentaglottis-sempervirens.html.
“INaturalist Observations”. 2021. https://www.inaturalist.org/observations?place_id=any\&taxon_id=166466.
18. Question 18
No
0
Very Low
Unknown. Some gardeners suggest seeds can get carried in pet fur. Seed has an elaiosome for ant dispersal.
Stuessi, Hans. 2021. “Picture of Seeds With Elaiosomes (including Pentaglottis Sempervirens)”. wikicommons. https://commons.wikimedia.org/wiki/File:Compilation_of_seeds_with_elaio….
Society, Royal Horticultural. 2021. “Green Alkanet”. Royal Horticultural Society. https://www.rhs.org.uk/advice/profile?PID=1001.
19. Question 19
No
0
Very Low
Unknown, very little information on dispersal outside of gardens. The seeds (nutlets) are relatively large and do not have adaptations for wind or water dispersal. The bracts that surround the nutlet do not seems to have adaptations for wind or water dispersal either, they are covered in prickly hairs.
No references cited.
20. Question 20
No
0
Very Low
Unknown, very little information outside of dispersal in gardens. No morphological adaptation to suggest long-distance disposals (no hairs, hooks, bristles, fleshy fruit). However the seed does have an elaiosome, which usually indicates dispersal by ants.
Stuessi, Hans. 2021. “Picture of Seeds With Elaiosomes (including Pentaglottis Sempervirens)”. wikicommons. https://commons.wikimedia.org/wiki/File:Compilation_of_seeds_with_elaio….
Evaluation Notes
Information on dispersal and invasability in natural areas not well documented. For example in the UK, the plant was introduced in the 1700's however many records of the plant are from after 2010. Which could indiciate it is spreading or it is popular with gardeners. Very few ecological studies on this species, the few studies consist of surveys of areas in Europe where this plant was found.
https://bsbi.org/maps?taxonid=2cd4p9h.ccv#style=N4IgzgpgTglhYgFwG1QAcCGU...
Added updated climate match map and link but did not check whether answer to #6 is still accurate. Also made minor corrections to references on new website (J. Burger 11/1/2925(=)
Total PRE Score
10
20
55
