All 89 bee plants
Holly pollen
Ilex aquifolium
Muted pale yellow, in the yellow range.
FloweringMay to June
PollenGood
NectarFair
SeasonSpring, Summer
WhereWoodland, Hedgerow, Garden
Only the male bushes offer pollen, and the bees work them quietly for a week or two.

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.