Gorgeous... I have a soft spot for these gardens, couldn't do them myself (not even the miniature one my daughter has!!), but they have this air of serenity that really appeals...
I agree with Bronnie about the colors- the three different monotones strike just the right note of variation yet simplicity. This is such a beautiful, peaceful picture. It'd be great to hang in a bedroom.
I adore these Japanese gardens, from the time I lived in Japan, they are very relaxing to watch and gets you in a philosophic mood - you have captured that feeling very well.