The photo on this listing is not ERIGERON kARVINSKIANUS!
This species can become invasive. They will tolerate dry soil which is not too rich. You will need to prune after flowering for a better shape, and this will also prevent unwanted self-seeding.
Propagate from seed or by division in spring.
Pests, diseases or disorders
Powdery mildew may cause problems.