We visited the Japanese Friendship Garden on Easter Sunday and it was a great little hideway in the desert. After a $5 entrance fee and buying a $0.50 cup of Koi food, we headed into the garden with a helpful map in hand. Of course, the garden is quite small (4 acres, I think) so it wasn't that we would have gotten lost without the map but it was very helpful at explaining the features that we were seeing and how they relate to traditional Japanese gardens and culture. Very interesting!
They also hold traditional Japanese tea ceremonies once a month for an additional charge. Keep in mind, the garden closes over the summer so be sure to check the website to see if they are open when you want to visit.
Overall, this was a great find in the PHX metro and we will be back to visit soon.