|'Cambridge Blue' is a showy and dependable edging plant that is categorized as a perennial. Compact growth habit with leafy, branching stems covered in sky-blue flowers ( three quarters of an inch across) from summer to frost. Will live through the winter in mild areas. Be patient with sown seeds as it can take up to 2 months for them to become transplanting size. Prefers moist, rich soil and will continue to self-sow once establishe.