As you have undoubtedly noticed there is something out there right now with pollen. On the recent warm days, in mid March, my bees (just up Dutch Hill road) have been coming back with lots of bright yellow pollen. I haven't been able to determine where they are getting it and may not since I am out of state now until the end of March. But maybe you can check out your bees and let us know what is blooming this early.
Below is a list showing beginning bloom dates for the last three years.
We would like to continue to add to this data for this and future years. In addition we'd like to add the area in the valley a particular date relates to (i.e., upper Dutch Hill, Middle Burnt Fork, east of Corvalis, etc. as specific as you can) and when applicable and possible when the particular bloom ends. We may try to incorporate this in the Bitterroot Bees Calendar so you can scroll through the calendar for potential bloom dates.
The column "GDD" refers to "Growing Degree Days" which is a measurement used to forecast crop growth. A little complicated - for more info see: http://wine.wsu.edu/research-extension/weather/growing-degree-days/ or