Heuchera sanguinea Engelm. (southern U.S.A., Mex.) – A very rare and mostly ephemeral escape from cultivation. First recorded in the wild in Belgium in 1955 when it was observed as an escape in woodland at the Chapelle Notre de Dame de Beauraing. In the past years obviously increasing and recorded in several widely scattered localities. An overview of recent observations is available here: https://waarnemingen.be/soort/view/142404. Most records are from urban habitats (cracks in concrete, foot of walls, pavements, etc.) and in the vicinity of planted individuals. However, it has also been observed in less artificial habitats, for instance in Vrieselhof in Oelegem. A future local naturalization seems likely. Similar behavior has been noted from the British Isles where it is considered a persistent garden escape (Clement & Foster 1994).
This species is much more frequent as an escape than H. micrantha and is often seen in larger numbers. Identical records are available from many other European countries, for instance Germany (Brandes 2016), Sweden (Svenson & al. 2001), etc.
Brandes D. (2016) Über einige Neufunde von Neophyten in Braunschweig und Umgebung. Florist. Rundbriefe 50: 37-59. [available online at: http://www.ruderal-vegetation.de/epub/brandes_flor50.pdf]
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
Svenson A., Edelsjö J., Ekman J., Gudmundsson H. & Odelvik G. (2001) Floran på tippar i Uppland och Södermanland 1990-1999. Daphne 2001-2 [available online at: http://www.bsis.org/Dokument/Daphne/2001-2%20Arter.pdf]