Seeds from Rudbeckia subtomentosa Sweet Black eyed Susan or Sweet cornflower. A very fragrant perennial with hints of anise. This large black eyed Susan, this native wildflower can be planted in sun to partial shade. Great for native wildflower gardens, meadows, and in formal flowerbeds . Sweet Black eyed Susan is a long lived perennial. Grows 3 to 5 feet in zones 3 to 9. Native Rudbeckia subtomentosa seed germination is improved after a pretreatment of 3 to 6 weeks of cool moist stratification or when planted outside in the fall or winter.