Board Thread:DC Universe Discussion/@comment-1635895-20121009211608/@comment-1038387-20130306141157

Some say red, some say strawberry blond. You decide. Bruce definitely made him dye it to look more like Dick, but I'm not sure if it was to remind him of Dick, or to make sure noone asked questions about the new Robin.

The red hair was originally retconned out with Crisis on Infinite Earths, but brought back during Batman Reborn.