Usually, African American strands are naturally dark due to which a lighter shade is likely to give an unnatural look. This means selecting a blonde shade will not work well for covering gray African American hair. A light shade gives a displeasing outcome of orange tinge or yellowish hue. However, in case of light gray hair, a lighter shade is recommended.
If the length of your manes is not gray and only the roots are gray, a permanent color is fine for having a dark brown hue for covering the gray on the roots after which you can have a deep cherry highlight for a cool look. You can even consider some deep tones of brown and black for covering gray portions on such strands. Brands such as Wella Koleston offer demi-permanent options for the same.