Twin arnica is a great plant-it-and-forget-it species that impresses each year with an increasingly larger island of cheerful yellow blooms.  In early spring low clusters of slender, soft green leaves hightlight taller spring ephemerals such as prairie star, shooting star, and larkspur. Flowering colonies of twin arnica can cover entire meadows. The plant goes dormant during our hottest months, and reappears with the fall rain. This prevents them from outcompeting other plantings. Fill the temporary gap with blanket flower, yarrow, and showy fleabane.
 
Important note: when the plant starts going dormant (varies year to year but around mid-late June) don't try to water it back into existence. Let the leaves wilt away, and water deeply only every one or two weeks to keep the roots alive.