Hedeoma diffusa is a species of flowering plant in the mint family known by the common names spreading false pennyroyal and Flagstaff false pennyroyal.

[1][2] This perennial herb has spreading, prostrate stems that form a mat on the ground.

The flowers are blue to lavender in color and are open for about three days.

[2] This plant is limited to northern Arizona, occurring in Navajo, Coconino, and Yavapai Counties.

In Oak Creek Canyon in the Red Rock-Secret Mountain Wilderness Area, sites are considered protected, and most are inaccessible.