California Citrus and the Mother Orange Tree

Although California has a long history of commercial cultivation of oranges and other citrus fruits, citrus trees are not native to California.

The homeland of citrus is southern and eastern Asia, Melanesia and Australia. Sweet oranges were introduced to the Mediterranean from Asia by Genoese and Portuguese traders in the 15th and 16th centuries. Franciscan missionaries brought sweet oranges to California around 1769. The first citrus orchard was planted in 1804 in the San Gabriel Mission, east of Los Angeles. The first commercial orange orchard was planted in 1841 near what is now downtown Los Angeles.

All early varieties of orange contained seeds. The seedless navel orange was the result of a mutation in a tree planted in a monastery in Bahia, Brazil, in the early 19th century.

The mutation caused the formation of a second primitive fruit at the end of the orange blossom within the primary fruit, forming a belly button-like depression on the outside of the fruit. This mutation also caused the fruit to be seedless.

In 1870 dozens of these trees were sent to the United States Department of Agriculture in Washington, DC. They were bred, and in 1873 the seedlings were sent to gardeners in Florida and California for testing.

Elisa Tibbets of Riverside received two seedlings that she planted in her front yard. Trees planted in Florida did not do well, but Eliza trees thrived in California. ‘Washington’ navel oranges had an exceptionally sweet taste, were easy to peel, winter-ripened and seedless. Within a decade, it became the most widely cultivated citrus fruit in Southern California and remains one of the world’s most popular navel orange varieties. In 1875 there were 90,000 orange trees growing in California. By 1901 there were 4.5 million concentrated in Los Angeles, San Bernardino, and San Diego counties.

One of the Tibbets seedlings that were planted eventually died, but the other is still alive and can be seen in the southwest corner of Arlington and Magnolia Avenues in Riverside.

What is likely the oldest living orange tree in California, grows in Butte County. The mother orange tree originated in Mazatlan, Mexico. It was planted in 1856 near the toll of the Bidwell Barre Suspension Bridge, which ran across the Middle Fork of the Feather River, after Judge Joseph Lewis purchased a 2- to 3-year sapling in Sacramento. The tree was planted twice. In 1862 it was moved to the other end of the bridge due to the danger of flooding. In 1964 it was moved to 800 Glen Drive in Oroville during the construction of the Oroville Dam.

According to one of the paintings on the tree, “In the early days miners traveled from far and wide to eat its sweet oranges, collect the seeds, and sow them in their yards.”

Joseph Connell, a retired University of California Cooperative Extension farm advisor, wrote, “Following the success of the mother orange, by 1863, 75 acres of orange trees had been planted in the county.”

Orange production in Butte County peaked around 1900, when 3,300 acres were set aside for orange cultivation. By 2007, oranges had decreased to 162 acres.

Mother oranges were damaged by severe freezing in 1990 and 1998. They stopped producing oranges, and their survival was in doubt. With additional care by Connell and California State Parks, Mother Orange has recovered from freeze damage and is producing fruit again. Additional efforts, including heat lamps and water mist, are being made to protect the tree from further damage.

In an effort to preserve the existence of its own genome, four new trees were propagated using wood buds collected in 2001 from mother oranges at the University of California Riverside’s Citrus Reproduction Protection Project.

Bodwood is a short, leafless twig with buds used for grafting on another plant for vegetative propagation. Two trees were planted in a variety of citrus fruits at the University of California, Riverside. The third and fourth were planted in Oroville, one in an orange grove next to Lott’s house in Sank Park and the other next to the Butte County Historical Society Museum.

A fifth, locally bred tree was planted around the same time at the Patrick Ranch Museum near Durham.

The Citrus Project began at the University of California Riverside in 1956. The first project of its kind in the world, the purpose of which is to provide a safe mechanism for the improvement of citrus cultivars, the introduction of new cultivars for research, and for the propagation of citrus for commercial or personal use. By law, every newly bred citrus tree in the state can be traced back to a parent tree created through the program. This requirement ensures that all new citrus plants are disease free. Incoming trees are tested for more than 30 citrus diseases. Any diseases identified in the first round of testing are eliminated by heat treatment of affected shoots or by using small pieces of growth tips for new propagation. All sprouts generated during treatment are again tested for citrus diseases. Once the new tree passes the screening tests, it receives a Variant Index or VI number necessary for release to the public. The latest variety index number, VI 1000, was awarded in June 2022 to a tree bred at UC Riverside using bud wood from a clone of the mother orange tree.

Called the “Bidwell Bar” variety, bud wood will now be available for purchase by commercial nurseries and citrus lovers. Information about purchasing podwood from Bidwell’sBar or other citrus species is available at the Citrus Project website https://ccpp.ucr.edu.

UC Master Gardeners is part of the University of California Cooperative Extension System, and serves our community in many ways, including 4-H, farm advisors, nutrition and physical activity programs.

Originally published at San Jose News Bulletin