Helianthus maximiliani, commonly called Maximilian Sunflower, is a native to the Great Plains and former tall grass prairie regions of North America. It is typically found in dry open areas such as prairies, bald knobs, bluffs, limestone glades, roadsides, and waste areas. [Plant finder missourbotanicalgarden.org]
The sunflower is named after Prince Maximilian of Germany, a naturalist who led an expedition to the west of America from 1832 to 1834. The Plant prefers moist, clay-like soil but is tolerant of a wide variety of soils. [Plants.ces.ncsu.edu]