Jovibarba heuffelii

Jovibarba heuffelii, common name Hen-and-chickens, as a plant species native to the Balkans and to the Carpathians in Europe but reportedly naturalized in Wisconsin and probably in other parts of North America. It grows on rocky outcrops.
"Jovibarba heuffelii" is a perennial herb forming basal rosettes of succulent leaves that are ciliate along the margins. Flowering stalks are erect, succulent, up to 20 cm (8 inches) tall, bearing a cyme of up to 40 white to yellowish flowers. Each flower is up to 5 cm (2 inches) in diameter, with 6-7 fringed petals. Each plant is semelparous, meaning that it flowers only once, dying after its fruits mature.
Some botanists treat the genus "Jovibarba" as part of the genus "Sempervivum," but the Flora of North America separates it into its own genus.