Variegated Yellow Archangel
The variegated yellow archangel (Lamium galeobdolon subsp. argentatum) is believed to be native to Europe (but its origins are unknown). It has become an invasive subspecies in several European countries, including the Netherlands, Britain, and Switzerland. It was introduced as a garden plant in New Zealand and North America (and probably elsewhere) where it escaped cultivation and became naturalized. In New Zealand, it is listed by the 2020 National Pest Plant Accord and therefore banned from sale, propagation, and distribution throughout the country. It is also listed by the Invasive Species Council of British Columbia in Canada. In the U.S. state of Washington, it is listed as a Class B Noxious Weed and therefore banned from sale by state law.
Botanists in Europe recognize four closely-related taxa, either as subspecies of Lamium galeobdolon or as full species, usually in genus Lamium but also in Galeobdolon or Lamiastrum. Most North American authorities recognize a single taxon, referred to as either Lamium galeobdolon or Lamiastrum galeobdolon. In any case, multiple taxa are not recognized in North America.
According to Flora Novae Angliae (2011), Lamium galeobdolon is confined to Maine and Massachusetts in New England. However, as of March 2024, there are hundreds of research-grade observations of Lamium galeobdolon subsp. argentatum spread across all New England states. According to New Flora of Vermont (2015), Lamium galeobdolon is said to be rare in Vermont (apparently based on a single specimen collected in Chittenden County in 2008), but as of March 2024, there are dozens of research-grade observations of Lamium galeobdolon subsp. argentatum scattered across 10 counties in Vermont. These data suggest Lamium galeobdolon subsp. argentatum is now widespread (and increasing) throughout Vermont and all of New England.
For more information, including numerous reliable sources, see the article on Lamium galeobdolon in wikipedia.
Observations
Photos / Sounds
What
Variegated Yellow Archangel (Lamium galeobdolon ssp. argentatum)Observer
trscavoDescription
Along the Potash Brook
Comments
Thanks for bringing this to my attention. I have never observed one and will be on the look out now. Heading north soon.
Thanks @hollyyoung see you soon! :-)
There are also numerous observations of this plant in Canada. Mostly Ontario, Quebec and British Columbia.
It is still wildely sold in garden centers as an ideal ground cover...
Unfortunately, the horticulture and landscaping industry continues to sell many invasives, such as this one. Few government instances proactively pass laws to ban invasives.
Thanks for brining attentio to this plant as an invasive.
Thanks @sygrnwd like other authorities in North America, VASCAN recognizes a single taxon (Lamium galeobdolon).
Of course you are right that the horticultural industry helps to spread invasives, including subspecies argentatum, which is often discarded as garden waste and then spreads rapidly via runners (stolons). For comparison, there is a cultivar of Lamium galeobdolon subsp. flavidum called 'Hermans Pride' that is also sold in North America, but since it has no stolons, it is mostly harmless.
@sygrnwd In British Columbia, subspecies argentatum is designated as a Regional Containment/Control species by the BC Provincial Priority Invasive Species List.
@moritz3 @comradejon @alex_abair
Can you check for accuracy? Thanks!
I'll say that this entity is treated differently taxonomically depending on which part of North America you ask. Synonymy aside, I know it's also a relatively new concern for the state of Oregon.
Thanks @alex_abair I appreciate the reply.
Are the taxonomic differences in North America beyond what I mentioned (either Lamium galeobdolon or Lamiastrum galeobdolon)? Do you agree that Lamium galeobdolon subsp. argentatum is not recognized in North America?
I'll see what I can find re Oregon. Thanks for the tip.
Well now I can't seem to find any North American floras that even mention infrataxa. Which is strange... When I worked on the Lamiaceae descriptions and keys years ago, I don't think this question was on my radar, so we just treated it as Lamiastrum galeobdolon. But yeah, I think your original assessment is more accurate.
I don't understand the logic of not recognizing L. g. argentatum as distinct from other L. galeobdolon infrataxa. The morphological differences across the infrataxa treated in Europe are significant. It also seems important that only L. g * ssp. *argentatum becomes established in North America. I have only seen L. g. flavidum 'Herman's pride' in cultivation (if I recall correctly).
In Oregon, Lamiastrum galeobdolon (a synonym for Lamium galeobdolon) is listed as a Class B Noxious Weed by the Oregon Department of Agriculture (ODA).
In an ODA bulletin (06/01/2020), it is claimed that a "B-Listed Noxious Weed Yellow Archangel reportedly seen for sale in Oregon". The plant in question was reportedly labeled as Lamium galeobdolon 'Hermann’s Pride'. In the bulletin, the ODA emphasizes "the importance of correct labeling and the ever-changing nature of Latin names in botanical nomenclature". They claim that "Lamium" is an older name for the genus that is synonymous with the newer name "Lamiastrum".
I think the ODA is off-base here. Both Lamiastrum galeobdolon and Lamium galeobdolon are in use, and based on current phylogenetic data, both are correct. The important point (which the ODA overlooks) is that there are four taxa. Failure to recognize these taxa leads exactly to this problem. Lamium galeobdolon subsp. flavidum 'Hermans Pride' does not have stolons and is therefore not invasive (as far as I know). The other three taxa do have stolons. Interestingly, only Lamium galeobdolon subsp. argentatum is known to be invasive.
In the journal article above, I noted that multiple taxa are not recognized in North America. I think that's an important point (but I need to do a better job explaining why this is important). When the ODA uses the name Lamiastrum galeobdolon, it is doing so sensu lato. Essentially it is listing the entire complex as invasive. It may be easier to do that but it's not technically correct.
@alex_abair our comments crossed paths. I'll read and reply to your asap.
@alex_abair I agree with everything you said in your previous comment.
The taxonomy of the complex outside of Europe is a mess. It might be easier to just list Lamium galeobdolon (or Lamiastrum galeobdolon) sensu lato, and then list exceptions (such as 'Hermans Pride') if and when they occur.
There's no strong reason (that I can see) to prefer Lamiastrum galeobdolon over Lamium galeobdolon, but if that becomes a North American "thing", I guess that's okay. For reference, the four taxa in both genera are explicitly named in the wikipedia article.
Also, the usage of Lamiastrum renders Lamium polyphyletic. I wish the name "Lamiastrum" would disappear! lol
@alex_abair do you have a reference? Everything I've read suggests Lamium remains monophyletic whether you segregate species or not.
I thought I did... Boy, my memory is really not serving me today. All the readings I have in my files do suggest Lamium monophyly is still preserved. I must have been confusing the histories of Eriophyton and Matsumurella with Lamiastrum.
At any rate, here is a relevant excerpt from Atalay et al. (2016) to justify my ill will towards "Lamiastrum":
"Lamium galeobdolon (L.) L., which is morphologically very distinct, has been included in seperate [sic] genera as Lamiastrum Heist. ex Fabr. or Galeobdolon Adans. On the other hand, Harley et al. (2004) and Govaerts et al. (2010) included the species in Lamium. According to the latest molecular phylogenetic studies by Bendiksby et al. (2011b) and Krawczyk et al., 2013, Krawczyk et al., 2014, including the species in a seperate genus is not suggested. "
Thanks @alex_abair I appreciate your input. I haven't seen the papers by Krawczyk et al. so I'll try to track those down.
Hey @trscavo! Nice write-up!
Thanks @comradejon!
Tom - thanks for the useful article. Here's what our King Country Washington noxious weed control people say: "Yellow archangel is a non-regulated Class B noxious weed in King County. Control is recommended but not required. Yellow archangel is also on the state quarantine list and can not be sold in the state of Washington."
https://kingcounty.gov/en/legacy/services/environment/animals-and-plants/noxious-weeds/weed-identification/yellow-archangel
I have eradicated this at Grace Cole Park but it requires maintenance, in fact, I just noticed a new patch. It's all over in the Puget Trough.
The Flora of the Paciifc Northwest, 2nd ed. lists this as Lamiastrum galeobdolon
@brewbooks thanks John, and keep up the good work!
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