Caryopteris incana (Houttuyn) Miquel (incl. C. tangutica Maxim.) (SE As.) – A very rare escape from cultivation. A single selfsown shrub was recorded in a crack of concrete in the center of Brussels in 2017.
Although widely cultivated Caryopteris incana is rarely (if at all) reported as an escape from cultivation.
Ando M., Kuwabara K., Matsubara K. & Watanabe H. (2016) Distribution and Phylogeography of Caryopteris incana (Lamiaceae) Based on Chloroplast DNA Sequences in West Kyushu, Japan. American Journal of Plant Sciences 7: 167-180. [available online at: https://file.scirp.org/pdf/AJPS_2016012816104474.pdf]
Itow S. & Kawasato H. (1988) The distribution and ecology of Caryopteris incana Maxim. (Verbenaceae) in western Kyushu, Japan (in Japanese). Hikobia 10(2): 135-143.