All 89 bee plants
Apple pollen
Malus domestica
Pale creamy yellow, in the cream / white range.
FloweringApril to May
PollenVery good
NectarYes
SeasonSpring
WhereGarden, Farmland
The orchard workhorse of late spring.

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.