I keep pretty good records, or at least I try to every year!
I'm seeing a pattern that you may be experiencing too. The hives that spent some time with the sunflower bloom, in late summer, seem to over winter better and have no noticeable nosema infection. This is a type of bee diarrhea that is lethal for bees trying to rebound after winter.
Check out Ian Stepler - as he talks about Sunflower and the beneficial effects to 'bee gut health'. This guy is fantastic! Great advice and some great ideas and experience.
You might want to consider planting some sunflowers in your garden next year for sure!
Sunflowers and Bee Gut Health
