I found this hand painted postcard at a vintage paper show. It is dated on the back, December 18, 1941 and was sent to Long Island, USA from New York City.
It took some doing (I had a hard time reading the handwriting), but I’ve identified the two botanical names inscribed at the bottom. The one on the left is Saponaria aka Soapwort, and the second on the right reads Menta Selvetica, which is Italian for Wild Mint. Both plants are depicted above their names.
Other plants appear to be red snapdragon, silvery leaves that look like wormwood (Artemisia), and something in the Aster Family, my best guess is hawkweed (Hieracium).
Note that the postal stamp is in keeping with World War 2 messaging: “Industry | Agriculture FOR DEFENSE.”