Question about henna and dark dyed hair.

Several months ago I used an all over dark brown dye on my hair. After looking at these henna pics, I'm in love with the red and wanting to give it a try. I tried to add red highlights in my hair with a hairdye made for dark hair, and it did not dye over my dark dyed hair. Can henna do this? I'm just afraid that if i do it all over, I'll have pretty red roots where my new growth is, and then yucky brown for the rest? Anyone tried this before?
Thanks in advance.
Thanks in advance.

"I feel no need for any other faith than my faith in the kindness of human beings. I am so absorbed in the wonder of earth and the life upon it that I cannot think of heaven and angels."
0
Comments
You can mix henna and indigo (to make it darker) and probably blend the old and new, making the new growth darker than it is naturally. But then you're going to have to keep that up. To totally get rid of the dark is going to require bleach or cutting, whether it's now or after you do what I already suggested for a while.
Keep in mind that henna is permanent, too, but at least you can color over it as long as it's body art grade.
Current Main Rotation: MG217 medicated or Aim2Health 'poos for scalp, Elucence cond., Spiral Solutions Protein & Deeply Decadent Cond., CJCCCC reg or lite,CJ Pattern Pusha,, Giovanni LA Hold Hair Spritz + lots more, sporadically
HG Method: Super Soaker + Smasters-ing, brief upside down diffusing w/360o diffuser then clips/clamps & air dry. Newly gray - stopped my henna glosses!
www.fotki.com/auntnett
This is after 6 applications.
My hair is still damp on the ends so they look darker but you can see my roots and the tops and the red color. It was orangy at first and it's getter redder with each application.
Current Main Rotation: MG217 medicated or Aim2Health 'poos for scalp, Elucence cond., Spiral Solutions Protein & Deeply Decadent Cond., CJCCCC reg or lite,CJ Pattern Pusha,, Giovanni LA Hold Hair Spritz + lots more, sporadically
HG Method: Super Soaker + Smasters-ing, brief upside down diffusing w/360o diffuser then clips/clamps & air dry. Newly gray - stopped my henna glosses!
www.fotki.com/auntnett