All 89 bee plants
Hazel pollen
Corylus avellana
Pale sulphur yellow, in the yellow range.
FloweringJanuary to March
PollenGood
NectarNone to speak of
SeasonWinter, Spring
WhereHedgerow, Woodland
Often the very first pollen of the year, worked on mild winter days when little else is open.

Easy to mistake for these
Closest pollen colours in our set, measured the same way the pollen identifier scores a match. Colour alone will not settle it, so check the flowering months and what is actually growing near your hives.
Out at about the same time
Saw a load like this going in?
Sample the colour against all 89 plants, then keep a forage record per hive.