After the birth of Edward, Ella became ill with tuberculosis and moved to Oracle, Arizona for her health.
The rest of the family joined her a year later, and John opened a general store.
Her daughter, Mary Howard Cadwell, was one of the first women in the United States to earn a Ph.D. in microbiology, and later became a professor at the University of Arizona.
[1] Some of Estill's watercolor paintings of cacti were included in the book The Fantastic Clan, The Cactus Family by John James Thornber and Frances Bonker.
The University of Arizona Herbarium contains almost 600 of Estill's watercolors in its collection.