Billie Eilish's neon green roots have certainly caught on. When it comes to 2020 hair colour, "people are being more and more experimental," says Wood. "Neon roots in particular challenge the eye and really stand out," adds Howard.
The trend focuses on a neon shade at the roots, which is feathered down about three inches toward the midpoint of the hair, gradually decreasing the saturation of the colour. The ends are left a more natural, often darker colour to make sure the contract really stands out. This is definitely a trend to try in the salon, though. "Colours we create today are never just one straightforward technique — it's much more about creating a bespoke look, always personalising every colour," says Wood.