From the essay "Warnings from the Grave" by Stephen Spender in The Art of Sylvia Plath, edited by Charles Newman (1970):
The landscape is an entirely interior, mental one in which external objects have become converted into symbols of hysterical vision:
This is my property,
Two times a day
I pace it, sniffing
The barbarous holly with its viridian
Scallops, pure iron
And the wall of old corpses.
I love them.
I love them like history.
The apples are golden,
Imagine it--
My seventy trees
Holding their gold-ruddy balls
In a thick grey death-soup,
Their million
Gold leaves metal and breathless.
'Letter in November'
We can enjoy the 'description' in this, the autumn-golden apples in the grey-soup mist. All the same, this nature is not the great furniture of the continuity of the seasonal earth, on which the distraught mind can rest. Or if there are some externals in these poems ... they in an atmosphere in which the external is in immediate process of becoming the internal, opposites identical with one another.
This reminds me of Van Gogh's landscapes, which express not so much what the artist saw as existing in nature, but more what existed in himself, projected onto it. A few weeks ago a Logan essay prompted the question how could nature ever appear in poetry in a way that could be new? Of course what Plath was doing 50 years ago now can't exactly be characterized that way.
From the introductory essay by Newman:
[In an early essay from the juvenilia s]he endows the sea with the characteristics of her own mind. .... It is not surprising then, to find in the last poems, that Nature herself is equated with, and even regulated by, the mind. .... [This] requires that imagination become equal to experience. .... There is no division between the world and her wilful representation of it.
The exertion of that will on the reality we commonly inhabit results in an art in which reality is not completely distorted, either beyond the reader's recognition or to the point of absurdity, but altered just enough to be interesting and new, but still feel true and plausibly real. The insight of this art feels somehow more true than everyday sensory perception, and far more true than narrative.
I'm constantly looking for poets who do this but the truth is I can't seem to find very many. Dickinson and Keats, Louise Mathias and Tomas Transtromer (translations of whose work I've just started reading) come to mind. One essay calls Transtromer's poetry "ensorcelated," or more precisely, says that it takes place in "ensorcelated places." The Spender essay calls Plath's work "emotional-mystical."
More from Spender:
Considered simply as art, these poems have line to line power and rhythm which, though repetitive, is too dynamic to be monotonous. Beyond this, they don't have 'form'. From poem to poem, they have little principle of beginning or ending, but seem fragments .... [T]he length of the poem is decided by the duration of the poet's vision, which is far more serious to the poet than formal considerations.