Serious studies began for Boon when he hosted Akio Kondo, Kihachiro Kamiya's first apprentice. Mr. Kondo arrived as what the Japanese call a first-year professional, and stayed at Boon's home for one year.

In 1993, the Golden State Bonsai Federation awarded Boon a Teacher Development Scholarship; two years later, he received the Ben Oki International Design Award for styling a Sierra juniper. In 1995, Boon received several informal offers to study bonsai in Japan. Months later he traveled to Japan where he studied bonsai for his first year as an apprentice with Yasuo Mitsuya.

Later, Kihachi-En became his “bonsai home” Kihachiro Kamiya, a great bonsai master with multiple national awards, became his master. Boon said once, “He showed me bonsai standards through his amazing talent and deep personal integrity.” Boon returned repeatedly to Japan for prolonged periods of bonsai study until his master’s passing in January, 2004.

In April 2000, Boon won the Grand Prize in the Kindai Bonsai Styling Contest in Japan (sponsored by Kindai Bonsai Magazine). Contestants styled large Japanese white pines. Boon was the only non-Japanese in the contest.

The World Bonsai Contest recognized Boon's trees in 2000, 2001, and 2002 as among the world's top 100 entries, and his students' trees have been recognized in every contest to date.

Today Boon makes his living as a full-time bonsai artist in Northern California. He styles client trees, lectures, puts on demonstrations, holds workshops, and finds show-quality bonsai for clients.