He was a musical maverick whose Trout Mask Replica still sticks out on best-of lists, but when he gave up rock to paint, his art was dismissed as doodles. Now his remarkable work is getting its due.

The singer-songwriter — who befriended the pioneering art-rock bluesman, whose real name was Don Van Vliet, late in his life — recited a poem he wrote for her in 2001 titled “Man Can’t ...