Garden Q&A: Why are our gardens being invaded by aphids?

A ladybird feeding on aphids. Picture: Alamy/PA
The RHS was right about an invasion of sap-sucking aphids thanks to a warm spring, if my garden is anything to go by.
In the past three weeks, I’ve seen wafts of greenfly smother the stems and buds of pretty flowering perennials and roses, while trademark trails of blackfly have appeared on my clematis.