In Ezra Pound’s poem “The River-Merchant’s Wife: A Letter,” images of vegetation appear in several places (especially at the beginning and end of the poem) and function in various ways.

In lines 2-4, for instance, the speaker mentions her memories of “pulling flowers” when she was a young girl (2). Perhaps she pulled them simply in a mischievous way; perhaps she pulled them for some more serious purpose. In any case, the reference to flowers suggests a kind of youthful beauty, as if the speaker is recalling a symbolic springtime in her life and the life of her eventual husband.  This suggestion of youthful innocence and beauty is reinforced by images of vegetation in the next two lines:

You came by on bamboo stilts, playing horse,
You walked about my seat, playing withblue plums. (3-4)  [emphasis added]

Here the references to bamboo and to plums are combined with balanced references to playing.  Both the boy and the girl are described during literally playful times in their lives. Nothing has as yet disturbed their youthful innocence.

Interestingly enough, references to vegetation now vanish from the poem for quite a few lines.  Such a reference seems to return implicitly in line 18, when the speaker mentions that “monkeys make sorrowful noise overhead” – presumably in trees (emphasis added). Here the tone of the implied reference to vegetation is much different than the earlier, explicit, references had been.  There the vegetation imagery had implied beauty and playfulness; here it is associated with the sorrow that results from the young couple’s separation from each other.

Later still, the vegetation references suggest various kinds of decay resulting from the passage of time.  Thus, in lines 20-22 the speaker reports that

By the gate now, the moss is grown, the different mosses,Too deep to clear them away!
The leaves fall early this autumn, in wind. [emphasis added]

All these images suggest the theme of mutability. The only growth reported here is the growth of a plant (moss) associated with death, while the reference to the falling leaves also suggests a transformation that is linked to death.  At this moment in her life, the speaker feels lonely and sad, and so it is not surprising that the vegetation imagery has changed significantly in its symbolic significance from what it had been much earlier in the poem.