In the 8 or so years that I have been on this site, I have always asked for anybody who finds a natural way to medicate for AD/HD to let me know. Nobody has ever responded. Furthermore, I have never seen any scientific tests that show any natural meds work. For them to work, they would have to increase the dopamine levels of the brain, and that is not something that you would want to play around with.
I am not sure what your fear of the meds are. They have been used for over 40 years, so the research is pretty good. But, that's neither here nor there. What is important is how can you help your son. The best way is for you to get all the information you can about ADHD, how it affects your child, and how you can help your child deal with this. A good starting point might be to read the links I gave in this post -
http://www.medhelp.org/posts/ADD---ADHD/idk-wat-am-doing-wrong/show/2208186#post_10587440
Please let me know if you need more information.