Marti

It won't leave because the hair absorbs the color deep into the cortex. You willl either have to re-color, or wait until your hair grows and then cut off the unwanted color. Even if you apply vegetable-coloring type colors to your hair, they don't just 'wear off' or wash out after so many shampoos, regardless of what the bottle says. Vegetable based colors coat the hair shaft and can leave unwanted 'green' tones in the effected hair. Regular 'pigment' based colors (ones that have to be mixed with an oxidizer or peroxide) penetrate the hair shaft and stain deep within the cortex - the part of the hair that is responsible for your natural color. They actually 'replace' your natural color with the pigments.

I'm afraid you are stuck with the color unless you bleach it out, then recolor to blend with your natural shade, or let it grow out and cut it off.