In searching for information about Japanese gardens in the United States, I came across the Japanese Gardening Organization in 2012. A delightful fellowship developed as my husband and I visited several gardens I found through members of the Board of Directors.
The web site of JGO developed into a photo-rich delight to the senses.
http://www.japanesegardening.org/site/
With the addition of chapters from Andrew Dean’s Complete Japanese Garden Handbook, the site has become information rich too.
Please give it a look.