It is said to enhance whatever level of dreaming one is developed in. For example, if one can not remember ones dreams, Mugwort will enhance and help the individual to develop this. If one is at the next level of dreaming, cognitive dreaming: (being aware one is dreaming and being able to "manipulate" the dream at will) Mugwort will enhance this.
The final level is precognitive dreaming; dreaming of future events.
No matter what level one is dreaming Mugwort will help you to develop your abilities. But beware, for until you become proficient your dreams may, at first, be difficult to deal with. Don't be discouraged; practice makes perfect. If you desire you might study under an experienced Dreamer or Shaman. Keeping a journal would be advantageous.
I have heard people say that their dreams become "techni-colored" after taking Mugwort.