I am located in Raleigh North Carolina. Tulip poplar started blooming April 18th. I am perplexed as each day I have looked up in the tulip poplar with binoculars at many blossoms and never see a single bee working. I've looked morning midday and late day why do I never see a single bee working the tulip poplar? Starting tomorrow we have a week of mid-80s temperature. Could it be the nectar only starts flowing once temperatures reach a certain point?