The Arnold Arboretum Bonsai & Penjing collection is one of the premier collections of Japanese bonsai trees in the United States. During the winter, the trees are held in cold storage to spare them the harsh conditions of New England winters.

Larz Anderson was an American diplomat who, throughout his life, served in Rome, Belgium, and briefly as the United States Ambassador to Japan. While Anderson had purchased two bonsai during an early visit to Japan, it was during his Ambassadorship that he and his wife, Isabel Perkins, developed a passion for the art form. They purchased 40 bonsai in 1913 and brought them to their home in Brookline, Massachusetts, on their return to the United States. After Larz' death in 1937, Isabel donated 30 of the bonsai to the Arboretum, and provided funds for their shelter, care and display.

Unfortunately, the collection suffered for several decades following the donation. There were basically no horticulturalists who had any knowledge of bonsai care in the United States, and approximately a dozen of the trees died between 1937 and 1962— including a tree gifted to the Andersons by Hirohito, then-Emperor of Japan. Six additional plants from the collection were stolen in 1986. Happily, the remaining trees now receive excellent care from trained Arboretum staff, and have thrived in recent decades.