Additionally, his connections with several other high-ranked former samurai-class residents of Kōchi—journalist Kayano Nagatomo, who was a Japanese supporter of Sun Yat-sen and was likely Ōtsuka's cousin;[8] politician Kenkichi Kataoka;[9] and politician Gotō Shōjirō[10]—make it likely his family was also of similar rank.

After that, he gained popularity by arranging urushi-lacquered (vermilion) taiko bridges, urushi-lacquered torii gates, stone lanterns, and weeping willows in small areas.Uehara also writes in the same book that "Tarō Ōtsuka...built many unique Japanese gardens in the central region of the United States.

During his career, Ōtsuka built numerous gardens in the Midwestern states, Florida, and upstate New York.

[15] As T. R. Ōtsuka, he advertised widely between 1911 and the early 1930s in national magazines including Country Life, House Beautiful, and The Garden.Clay Lancaster comments on Ōtsuka:[16] The Midwest has participated less vigorously than the East Coast in the Japanese garden movement.

During the interim, he had learned that the hinterlands remained relatively provincial in accepting imported modes.

From 1911 to 1916, Ōtsuka's garden business address was in the Fine Arts Building at 414 South Michigan Avenue across from Grant Park in Chicago.

Beginning in the early 1920s, the Ōtsukas began spending winters in Yamato, Florida (a Japanese community near Miami),[21] and they moved to New York City in late March 1924.

[24] Uehara writes, "After his wife's death, Mr. Ōtsuka returned to Japan alone and later went to China, but his whereabouts disappeared afterward.