Zones: 3 to 9
Size: To 2' tall and wide
Growth Rate: Moderate
Exposure: Sun, Filtered Sun
Larger flowers than the variety, to 4" diameter. Blooms throughout summer. Yellow petals with almost black center. Dark green foliage. Moist soils.
Found in a nursery in Czechoslovakia in 1937.
Perennial plant of the year in 1999 (Perennial Plant Association).
I purchased a 1-gallon plant from Evergreen in April 2011 and planted it in the front by the road on the right side of the driveway. It grew steadily and started blooming strongly in July.