@zuzu, I don't know why you doubt it, but planta is feminine and hediondo is an adjective meaning stinking the same as hedionda. When attached to a masculine noun it is hediondo and when attached to a feminine noun it is hedionda. I think the misunderstanding in regards to Bosea is that, the adjective hediondo, is being used as a noun. If you were to say "Bosea es la planta hedionda" (Bosea is a stinking plant) then Lavanda would be correct. But, in spanish, nouns do not shift gender, like adjectives do. So, since Hediondo is being used as a noun, only the one version would apply. I am not familiar with Bosea so I have no idea if they stink but, the words hedionda/hediondo has other meaning depending on how it is used.
http://www.spanishdict.com/tra.... So if the plant doesn't stink then, why that term was used is anybody's guess.
