I was a commercial beekeeper for about 20 years.
Believe it or not Honeybees are picky when it comes to working the flowers.
I don't think grapes or asparagus flowers appeal to Honeybees.
Most fruit trees do attract bees, if the weather cooperates, spring time when flowers bloom, the weather is very spotty.
Honeybees need about 50 degree, and above temps to fly to flowers, rainy, foggy, and cold weather, will inhibit bee flight.
Good Luck !