I have tried very late addition citrus blossoms in mead - fermentation complete late. I used citrus honey mead of varying degrees of sweetness. I played around with the volume and type of flowers added too (orange, tangerine, grapefruit, lemon, and lime). The result was a floral aroma somewhat different than what the blossoms smell like at their peak on the tree. Try smelling a blossom on the tree that has gone past its peak. It is simular to that. The aroma fades pretty quickly with time in the bottle.
Making a blossom tincture with Everclear seemed to capture and transfer to the mead the fresh-blossom aroma, but that too faded pretty quickly in the bottle.
I did these trials about 10-11 years ago when I lived in Orlando. I had 10 full grown citrus trees in my yard, and access to many more. Mrs. Punatic, who loves mead, encouraged me mightily to keep trying. We both love the scent of citrus blossoms.
Here in Hawaii I have coffee (and citrus too). I've been eyeing the coffee blossoms. They smell very much like citrus blossoms, and bloom at the same time. Perhaps next year... Every coffee blossom picked is a bean not roasted. My trees are still youngish and enough blossoms to experiment with would make a noticable reduction in beans.