These wasps visit every summer to dig underground burrows and fill them with paralyzed cicadas that will be food for their grub-like larvae.
The females have stingers which they use to inject venom into cicadas to paralyze them. They are not aggressive however, and do not have nest-guarding instincts. Males on the other hand lack stingers, but are territorial. They approach anything that enters “their territory” and may hover or challenge trespassers, but are harmless.
So, feel free to walk through and see the roses! Or enjoy these rose photos in the meantime.