As a young boy growing up in southern Texas, Onderdonk was an avid drawer and painter. His mother was Emily Gould Onderdonk, and his father, Robert Jenkins Onderdonk, was a painter and art teacher. He came from a background of a cultured Dutch family, especially as his grandfather, Henry, was the Headmaster of the independent boarding school named Saint James, in Maryland. Onderdonk’s father graduated at the Saint James School.
Onderdonk began his formal art training during his teen years, not only by his father but also studying under Verner White, known for his landscapes and portraits. Even though he was already invested in an artistic career, Onderdonk attended and graduated at the Texas Military Academy by the age of eighteen.
A year later, in 1901, Onderdonk left Texas for Long Island, New York, to study painting under William Merritt Chase, an Impressionist painter who had previously mentored his father. Chase was the director of the Shinnecock Hills Summer School of Art, a program that began in 1891 and ended in 1902 in which Onderdonk participated.
Onderdonk continued under Chase’s tutelage until moving to New York City to try his career as an artist. His work was mainly made of en plein air pieces, a technique popularized by the French Impressionists who painted mostly outdoors. During this time, Onderdonk met Gertrude Shipman, who he would marry and have a daughter named Adrienne.
In 1909, the American artist returned to his hometown of San Antonio, Texas. Onderdonk concluded some of his most successful paintings throughout the next two decades. His most famous paintings portray beautiful fields of bluebonnets like seen in A Cloudy Day, Bluebonnet Field, Bluebonnets, Late Afternoon, among others.
The Witte Museum was created from Onderdonk’s San Antionio art studio in Brackenridge Park and was established as a museum four years after his death. His masterpieces are also highlighted at the Dallas Museum of Art, which dedicates some rooms to his work. During the George Bush administration, the president chose three of Onderdonk’s paintings to hang in the prestigious Oval Office.
The American painter contributed significantly to the course of landscape painting in Texas and the USA. A collection of his artworks can be seen in the book Julian Onderdonk: A Catalogue Raisonne, a result of twenty years of research. A selection of twenty-five paintings was curated by the San Antonio Museum of Art for an exhibit in 2017.
One of his last paintings was Dawn in the Hills, an Impressionistic landscape painting with yellow skies and his characteristic portrayal of a field of bluebonnets. The artist used dark and muddier pigments compared to his earlier works.
Robert Julian Onderdonk passed away in October 1922, in his hometown of San Antonio, Texas.