Mesh hole size to get bees above head height

[wessexmario]

It seems to be not the size of the holes, but the size of the fabric of the net/trellis that matters.
If it's too fine then the bees don't see it, if it's thicker then they fly over/around.

 

[Obee1]

I have a six foot hedge iabout 2 feet in front of my hive. They fly straight up and over on way out. On the way back a few of them arrive from different directions. When my husband got creative with some topiary he cut some large spheres in the hedge leaving a low point near the hive. Luckily they still go to the old high height. Just as well as there is a pavement the other side of the hedge and people are oblivious to the bees above them. I have confiscated hubby's hedge trimmers till he can put the bees welfare ahead of his topiary experiments.

Obee