Perovskia Kar.
Perovskia is a genus of seven species native in an area that ranges from Iran to India. Some species are increasingly cultivated as ornamentals in European gardens (see Grant 2000 for an up-to-date overview).
Although debated at first, based on molecular data the genus Perovskia (and some other small genera like Rosmarinus) are better included in a broadly circumscribed genus Salvia (Drew & al. 2017 and references therein).
1 Leaves linear-lanceolate, entire to 1-pinnatipartite=== Perovskia atriplicifolia
Leaf blade ovate-oblong, 2-pinnatipartite === P. abrotanoides
Literature:
Bokhari M.H. & Hedge I.C. (1971) Observations on the tribe Meriandreae of the Labiatae. Notes Roy. Bot. Gard. Edinburgh 31(1): 53-67.
Darke F.P. & Tucker A.O. (1989) Identification of Perovskia species (Labiatae) cultivated in North America. Baileya 23: 54.
Drew B.T., González-Gallegos J.G., Xiang C.-L., Kriebel R., Drummond C.P., Walker J.B. & Sytsma K.J. (2017) Salvia united: The greatest good for the greatest number. Taxon 66(1): 133-145.
Gorshkova S.G. (1977) Perovskia. In: Shishkin B.K. (ed.), Flora of the U.S.S.R., vol. XXI. Academy of Sciences of the USSR: 267-272.
Grant M.L. (2000) Perovskia. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 6. Cambridge University Press, Cambridge: 205-206.
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Kovalevskaya S.S. (1987) K sistematike sredneaziatskikh vidov roda Perovskia Kar. (Labiatae). Uzb. Biol. Zhurn. 5: 48-50.
Rechinger K.H. (1982) Perovskia. In: Rechinger K.H. (ed.), Flora Iranica 150. Akademische Druck- und Verlagsanstalt, Graz: 476-479.