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. states of Washington and Oregon, 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.
The invasive subspecies argentatum is readily distinguished by its silvery white variegated leaves. It is sometimes confused with a cultivar of subspecies flavidum known as 'Hermans Pride', which also has silvery markings on its leaves. Unlike subspecies argentatum, however, subspecies flavidum is not stoloniferous, and therefore 'Hermans Pride' is not invasive.
For more information, including numerous reliable sources, see the article on Lamium galeobdolon in wikipedia.
