This cultivar is a cross between
H. 'Swoosh' and H. 'Hadspen
Heron' was registered by
Roy Herold in 1999.
It forms a large size (21 inches high) mound of foliage with prominent waves
and margins that may streak. Medium purple flowers bloom from July into August.
The Hostapedia by
(2009) states "The rapidly rising popularity of 'Dark Star'
is not surprising considering its striking combination of wavy,
white-margined foliage, dense mound habit and good growth rate."