Thank you!

festuca glauca 'Elijah Blue' is in the Front of this photo followed by Senecio serpens just beyond the gravel ring.

What temperatures does this plants need? Can they survive with little frost in winter?

Best to consult your local nursery or Sunset Western Garden Book's zones for your area.

Curious to know what the opaque material is you are using in the gate. And, do you know how well it is holding up with the climate there?

Looks as new as the day it was installed (4-5 years ago). It was specified as opaque tempered glass.... I know it is glass.... it's certainly opaque .. assuming it is tempered.