To propagate Ligularia, the most common and recommended method is by dividing the plant clump in early spring or late summer, using a sharp knife to separate the root crown into smaller sections with shoots, and then replanting each division individually; you can also try sowing seeds in a cold frame during spring or autumn, though this method can be less reliable. 

Key points about propagating Ligularia:

Division is best: This is the easiest and most successful way to propagate Ligularia, as it readily forms clumps that can be divided. 

Timing: The ideal time to divide is either early spring when new growth emerges or late summer when the plant is nearing dormancy. 

Process: Dig up the entire plant, exposing the root system. 

Use a sharp knife or spade to carefully cut the root crown into sections, ensuring each division has multiple shoots and roots.  Plant the divisions in well-draining soil, spacing them appropriately.  Water thoroughly after planting. 

Seed propagation (less common): 

Sow seeds: Sow Ligularia seeds in a cold frame or seed tray in spring or autumn. 

Germination conditions: Keep the seed starting mix moist and provide adequate light, as seeds need light to germinate. 

Potential challenges: Seed propagation can be less reliable as germination rates may vary.