Heliotrope is an odd duck, because while it's a flower, the scent is more like food. To be exact, heliotrope smells like fluffy, powdery almond mixed with syrupy cherries. There's almost a vanilla sweetness there at times. Imagine a flower that smells like cherry pie topped with almonds and marzipan. Hungry yet? Not all heliotrope notes smell like all of these things. Cherries and almonds are a classic scent combo because they share some scent characteristics (a certain sharp "high" fruity note is common to both) so in real life, a heliotrope bush may smell lighter, more like vanilla, more almondy, etc, depending. Heliotrope as a note has a very distinctive smell that does well in sweet, strong floral blends. It's can be adapted to suit aquatic or fresh/green formulations in small quantities.
Perfumes featuring heliotrope:
NAVA Ariadne: Definitely supposed to be a "soliflore" type of perfume highlighting the brazen and unusual heliotrope qualities. This smells like baking with almond extract and canned red cherries. Very sweet, a bit tart and red, and syrupy smooth.