A is for achillea, a wonderful perennial that has an ancient history. It is named after Achilles, the legendary Greek hero. He was the son of the sea goddess Thetis and the mortal king Peleus. Thetis, wanting to make her baby invulnerable dipped him into the River Styx. She had to hold him my his heels which never became wet leaving that spot vulnerable. Hence comes our saying that someone might have a weakness, an ‘Achilles heel.’ The…