Strictly speaking, there were [among Sufi poets] no such distinctions as “mystical poetry” and “non-mystical poetry”. Verse was a vehicle for the expression of transcendental experience, and this was not considered “non-rational”. It was the norm. Emily Dickinson, a non-Eastern poet, would not disagree with this:
By intuition, Mighty Things
Assert themselves – and not by terms –
“I’m Midnight” – need the Midnight say –
“I’m Sunrise” – Need the Majesty?
Omnipotence – had not a Tongue –
His lisp – is lightning – and the sun –
His Conversation – with Sea –
“How shall you know”?
Consult your eye!
Her body of work could for all intents and purposes be labeled ‘mystical’ (and indeed has). Certainly, her themes and concerns were of a transcendental nature.