15" x 18" wide. (cutting propagated). Introduced to the U.S. by Dan Hinkley, this is an improvement on the taller flower cultivars like _Herrenhausen._ 'Rotkugel' is more floriferous and has a more mounding habit in flower. The plant forms low-spreading stoloniferous mats of foliage that come into bloom from August through October. The flowering stems have large, loose heads of bi-color flowers with dark purple calyces and deep pink flowers. Butterflies love this plant! Zones 5-9.