[1] She rose to lead the USDA staff artists, and she became the most prolific of the group, contributing one-fifth of the 7500 paintings in the Pomological Watercolor Collection.

There, she found inspiration in the botanical illustrations of Marianne North at Kew Gardens, England, and when she returned to the United States, she began painting the wildflowers of America as well as lilies and other flowers.

[6] She hoped to publish these watercolors under the title Flowers in Water Color: Wildflowers of America, but she never managed to do so and the manuscript is now in the USDA's Special Collections.

This was a time when the major fruit-producing regions in the United States were just beginning to emerge, as farmers worked with the USDA to establish orchards for expanding markets.

Photography was not yet in widespread use as a documentary medium, so the government relied on artists like Passmore, Amanda Newton, Elsie Lower, Ellen Isham Schutt, and Royal Charles Steadman to produce technically accurate drawings for its publications.

"[8] Passmore's artwork for the USDA covered a wide range of fruit including apples, pears, plums, peaches, oranges, persimmons, strawberries, and gooseberries as well as the less-common loquat, kumquat, and Surinam cherry.