Fertile florets pink in bud opening pale blue, surrounded by pure white sterile florets.  (description ofDerbyplants)

Gardens found in 28 pre 2000 surveys DA (our plants may be wrong) LHS WIN TR RW ABJ WAA MS

Gardens found in the 10 surveyed in 2010: DA  LHS ESV AW

UK  Plant Finder 2012 = 1 nurseries