The was a flower show/sale at our local cooperative extension and our bee club had a booth with honey, charts and an observation hive (fake but none the less). My mentor tells me that goldenrod honey in light. I thought the opposite from my experience from the state fair. He says goldenrod is light but knot weed (bamboo) is dark and they bloom at the same time. It doesn't take a lot of bamboo nectar to discolor golden rod so dark goldenrod has bamboo in it. If it it dark he sells it as bamboo.