A spiky garden discovery in Silverton, Oregon

I would have driven back to take better photos, but Silverton is about an hour south of here, so not a quick adventure. 

Andrew noted the similarity to my plant palette: Dasylirion wheeleri, Arctostaphylos, Agave ovatifolia, Yucca rostrata. If only I had that amazing white-spined cactus and a monkey-puzzle tree, Araucaria araucana...

I counted three large Agave ovatifolia, two of them quite large. There was also what I think may have been an Agave 'Blue Glow' and an Agave parryi. But that's just what I could see from the street. No telling what treasures may have been lurking up by the house.
I love their tall metal panels used as fencing and the short metal box planters completing the border run to the street. The pathway with it's inset metal pieces is also pretty spectacular. I wonder if these folks just love metal, or if there's a professional tie-in? 
I wish I would have paid more attention to the tree on the left side of this photo, it might be a Quercus hypoleucoides, the silverleaf oak?
Another stunning pathway, I wonder how the green rounds are kept in such a tidy patch? They perfectly mirror the round manhole cover. Check out that big patch of opuntia!
Another chunky cactus
The manhole cover says City of Salem, Oregon's capital city which is about 15 miles west of Silverton.
I am in love with this garden! I wonder what's going on in the back of the house? Fingers crossed they read my blog—or someone who does read it knows the gardeners?—and I can score an invite to tour? Perhaps there are better photos in the future, complete with whatever is going in that large metal planter on the corner...