The plant may overwinter outdoors if protected. They may also be dug in the fall and stored through the winter. The foliage resembles that of iris. These are followed by clusters of black seeds that give the plant its common name. Iris borer could be a problem.
Propagation is by division in the spring.
Getting a blooming size plant from seed takes 3 to 4 years. This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information becomes public property upon publication and may be printed verbatim with credit to MSU Extension. Reprinting cannot be used to endorse or advertise a commercial product or company.