Possible Clues:

• Flowers in a Whitman verse
• That's how I calls them in the shrubbery
• Subject for Chagall and Cassatt
• By fifty-one lakes in France we'll gather them in spring, perhaps
• Relatives of ashes
• Second word in a classic Whitman poem
• Sweet-smelling bloomers
• Purple blossoms
• Whitman's 'When -- Last in the Dooryard Bloom'd'
• ''We'll gather ... in the the spring'' (Ivor Novello song)