Common rush can be propagated through rhizomatous offset division or from seeds. Rhizomatous offset division involves separating the basal offsets from the main plant and planting them in separate pots with well-draining compost. This method is best done during the summer when the offsets have at least two mature leaves. Seed propagation involves collecting the seeds from the plant and sowing them in a suitable growing medium. Both methods require proper care and maintenance to ensure successful propagation.