NEW YORK  — John Ashbery, an enigmatic genius of modern poetry whose energy, daring and boundless command of language raised American verse to brilliant and baffling heights, died early Sunday at age 90.

Ashbery, winner of the Pulitzer Prize and often mentioned as a Nobel candidate, died at his home in Hudson, New York. His husband, David Kermani, said his death was from natural causes.

Few poets were so exalted in their lifetimes. Ashbery was the first living poet to have a volume published by the Library of America dedicated exclusively to his work. His 1975 collection, “Self-Portrait in a Convex Mirror,” was the rare winner of the book world’s unofficial triple crown: the Pulitzer Prize, the National Book Award and the National Book Critics Circle prize. In 2011, he was given a National Humanities Medal and credited with changing “how we read poetry.”