Possible Clues:

• Plant with sword-shaped leaves
• Plant bushy lilac again with only eastern-facing pairs
• Is this a flowery way to greet Cynthia?
• The sound of a friendly greeting to a girl you know, till all is blue (8)
• Plant making most of hand itchy somehow
• Any hitch could be disastrous for this flower
• Sounds like a familiar way to greet Cynthia till all is blue
• Fragrant lily
• Hullo, Cynthia! You're looking blooming blue
• The way you might be greeting Cynthia till all is blue