I don't know much of Plath's writing and I found this in an anthology a few years ago and marked the page. The poem, like the mushrooms it describes, is both undemonstrative and yet insistent. There are some gorgeous and unusual repeated sounds, for example

"Over night ... whitely ... quietly" 

".... soft fists insist ..."

The use of sound and rhythm in this poem is a useful reminder that it's not necessary to be loud, obvious or to tower over others to be meaningful or even powerful.

Read the text of the poem here: https://allpoetry.com/poem/8498359-Mushrooms-by-Sylvia-Plath