New growth, hair color, frizzies

I have a question about growing out hair color. I've been coloring my hair blonde for 8 years. If I let the color grow out and get back to my natural hair color, would it repair itself and get rid of the frizzies? The reason I ask is because I have frizzies pretty bad where I have colored my hair. If I let new growth come through at the roots, my hair is soft and straight. I was just wondering if I let all the hair color grow out would all of my hair be soft and straight? Thanks!!