Believe it or not, this is not one of Pound's most difficult poems. It lacks the wide range of foreign vocabulary and obscure allusions that characterize his later poems, such as Hugh Selwyn Mauberley and The Cantos. You don't need to have read anything else, not even Henry James's The Portrait of a Lady, to understand this poem. However, Pound can't seem to resist throwing in a few curiosities here and there. Those of us who are not experts in magical roots or whale secretions will have to turn to Google (or Shmoop) to find out what "mandrakes" and "ambergris" are.
On the plus side, apart from the title, Pound keeps the poem in grammatically correct English. The grammar is, however, fairly complex, with multiple phrases layered on top of one another, and the poem jumps from one image or metaphor to another without explaining all the connections, making it difficult to follow exactly what the speaker is saying about the woman.