The Meadow Makers' Network Forum

Analysis of honey reveals changes in nectar sources over the last 65 years: decrease in white clover, increase in bramble and the spread of Himalayan balsam.

https://botanicgarden.wales/honeybees-t ... -65-years/

They have also shown the importance of dandelions as well as bramble for foraging honey bees. Interestingly, how much pollen from wind pollinated species such as grasses and trees (e.g. willow) turns up in honey.