A zen poem by an American - how did he know?

My favourite poems have always been the ones I don't really 'get'. Wallace Stevens' poem 'The Snowman' is one of those and I wish my memory would allow me (or I would give myself time) to learn it off by heart as it is a good one to remind one of the mysteries of life. After it became a favourite, I then found an article that declared Wallace Stevens to be a Zen poet and said why. That made me happy. Here is the poem:

The Snowman
One must have a mind of winter
To regard the frost and the boughs
Of the pine-trees crusted with snow;

And have been cold a long time
To behold the junipers shagged with ice,
The spruces rough in the distant glitter

Of the January sun; and not to think
Of any misery in the sound of the wind,
In the sound of a few leaves,

Which is the sound of the land
Full of the same wind
That is blowing in the same bare place

For the listener, who listens in the snow,
And, nothing himself, beholds
Nothing that is not there and the nothing that is.