Usually, a card’s color is determined by what colors are in its mana cost. But lands don’t have a mana cost, so they’re naturally colorless. But other effects can give a card color. For instance, sometime the spell or ability that animates the land will specify a color. Awaken the Ancients is the example of one: it will make the enchantment Mountain red. But Anthousa doesn’t say anything about giving the lands colors.
So, in the end, since the lands don’t naturally have a color, and because Anthousa doesn’t give the animated lands a color, the animated lands will not have a color (which might be beneficial, if your opponent gave their white army protection from green with Brave the Elements).
Today’s Rules Tip written by Nathan Long