Pollen source from coastal NC?

[iluvbees]

During this recent warm spell I saw my bees bringing in a lot of grayish-yellow pollen. I couldn't find them on any of the sources I would have suspected like Henbit, Dandelion or Red Maple. I was wondering if my NC neighbors have any clues?

[Walliebee]

The elms and plums have light gray pollen. Red Maple is a gray/brown color. There are many other ornamental plants in flower now in NC that it could be from as well.

[iluvbees]

Thanks Walliebee.