I took a picture of my bees working the frostweed that I will link below. I think they must collect nectar from it, because I don't see any of the bees working it carrying pollen. It's a broad-leaf perennial that grows back from the roots yearly, after the tops die off. The height is about 5-6 feet, and it spreads from the roots. It also grows from seed easily, in my experience. I noticed when checking my hive yesterday, that a good amount of new honey stores are being formed. Lots of it is still uncapped, so it is a current source.