A new and distinct cultivar of Chrysanthemum plant named `Yowilma`, characterized by its compact, upright and outwardly spreading plant habit; freely branching habit; dense and full growth habit; uniform and freely flowering habit; decorative-type inflorescences with elongated oblong, ligulate or obovate-shaped ray florets; white-colored ray florets; and natural season flowering about October 1.sup.st in the Northern Hemisphere.