Hi Maria,
if shooting in Italy not before May is an option I can help you.
Stinging Nettle (Urtica dioica) is easy to find everywhere, that is not a problem.
Rodiola Rosea we can find in the Alps, I know exactly where, but it lives in the high mountains between 2.000 and 3.000 mt, where now there is a lot of snow.
I’m obviously talking of wild plants, not cultivated.
I’m a location manager but with a background of agriculture and botanical studies, so I have a certain knowledge of these kind of matter.
Don’t esitate to contact me for any further informations
semplici@scoutit.it
http://www.scoutit.it
+39 335 6752614
Ciao
Leonardo Semplici