The Iwasaki Brothers Nursery, located on the southern edge of Hillsboro in Washington County, is on the fertile Tualatin Plains along the Tualatin River. It is the homeland of the Tualatin people, but during the early to mid-nineteenth century the plains became a coveted locale for agricultural settlement by American emigrants and former Canadian fur trappers. Following the Donation Land Claim Act of 1850, the area became thickly settled, and in 1855 the Tualatin and other Willamette Valley tribes and bands signed a treaty with the federal government that resulted in their removal to the Grand Ronde Reservation. The town of Hillsboro was established at the turn of the twentieth century, a few years before the Iwasakis moved to the Tualatin Plains to establish their farm.

Yasukichi (Billy) Iwasaki (1876–1968), a Japanese emigrant, traveled first to the Puget Sound area. He and Ito (Baba) Iwasaki (1890–1981) married in 1910 and were farmworkers near Sumner, Washington, where their son George (1912–2009) was born. The family moved to Washington County in Oregon in 1913, and in 1916 or 1917 the Iwasakis purchased a farm of 46.55 acres bordering Minter Bridge Road. Between 1916 and 1931, the couple had seven more children.

The Iwasakis raised about thirty dairy cows, selling their milk to a nearby Carnation evaporated milk plant. They added row crops of vegetables during the 1920s and built a glass greenhouse in 1928 to raise bedding plants. By the 1930s, the family was raising tomatoes, cucumbers, asparagus, corn, and strawberries, then blackberries, boysenberries, broccoli, and cauliflower during the 1940s. The three sons—George, Ike (Akira), and Arthur—ran the farm as a family operation. At night, the brothers trucked their farm products to the Portland produce market, returning to Hillsboro in time for school and work the next day.

In 1941, the family built a new house. George Iwasaki married Tomiko Natsuhara on February 22, 1942, three days after President Franklin Roosevelt signed Executive Order 9066, which removed West Coast persons of Japanese ancestry to inland incarceration camps. The Iwasakis were sent to Minidoka, Idaho, but were soon assigned to agricultural work near Nyssa in eastern Oregon. Ike and Art Iwasaki joined the U.S. Army and served in the 442^nd Infantry Regiment, a segregated unit comprised primarily of second-generation, or Nisei, Japanese Americans.

During the war, the Iwasakis’ farm was entrusted to neighbors, who returned it to the family at the war’s end. The three brothers managed the farm together, and in the late 1960s the operation became Iwasaki Brothers. They replaced outdoor farming with a greenhouse, where the Iwasakis raised spring bedding plants, supplemented during the 1970s by the production of Christmas wreaths. Art Iwasaki left the farm in 1978 to establish Tanasacres Nursery in Hillsboro.

The traditional Japanese line of succession placed George Iwasaki’s son Jim (b. 1943) at the head of the nursery’s management in 1997. Iwasaki Bros., Inc., now managed by James Iwasaki and his daughter, Julie, is wholly a greenhouse operation that produces bedding plants sold primarily through retailers such as Fred Meyer and Bi-Mart in Washington and Oregon. The original farmland is still in use, along with acreage added over the decades. The continuity of family ownership and management in the early years of the twentieth century resulted in the 2017 designation of Iwasaki Bros., Inc. as a Century Farm by the Oregon Century Farm & Ranch Program.