I wouldn't have said it smelled like lemons, but my first thought was that meant a cut lemon fruit. Then I started to wonder, maybe they mean the flowers of a lemon tree, not the fruit - Googled for that and found a blog that says "Finally, a real spring charmer, earlier than the regular daylilies, Hemerocallis lilioasphodelus, the lemon lily. Rather than smelling like lemons it smells like orange or lemon flowers, and has a nice strong scent unlike regular daylilies."
http://weedingonthewildside.bl...