According to the online system The Plant List, "Hesperis flava Georgi is an unresolved name ". More details, including synonymy and other links are available at:
I do not know the taxon but one possibility is that it grows as a biennial in regions with a short growing season and as a perennial in regions where there is no season that selects for shutting down the above ground parts. Just a possibility. It happens in grasses although, in the cases I am aware of it is a matter of switching between annual and perennial (possibly a short-lived perennial) rather than biennial and perennial.
Dr. Arvind Singh, I have read your answer again, and i completely undrestand what did you mean.
Dr. Gaston and Dr. Kadry: I have checked it before; if you see the question again i have mentioned about its new name, but any way thank you for your answers.
Dear Dr. Barkworth thank you so much for detailed answer. it is helping for me so much.
Dear Liza, i am agree with your answer to some extent.
greetings. I am afraid that your question is not within the area of my expertise. My area of work is soil and environmental sciences. people with expertise in plant taxonomy should be able to answer your question in detail.