To propagate Rodgersia, the most common method is by dividing established clumps in early spring; simply dig up the plant, carefully separate the root ball into smaller sections with a sharp knife or spade, and replant each division in a new location, ensuring each section has a good root system and shoots present. 

Key points about propagating Rodgersia:

Best time to divide: Early spring is ideal, as the plant is just starting to emerge from dormancy. 

Preparation: Water the plant thoroughly a day before dividing to loosen the soil. 

Division process: Use a garden fork to lift the entire clump, then carefully separate it into smaller sections with a sharp tool. 

Replanting: Plant the new divisions at the same depth as the original plant, ensuring good soil contact and watering well. 

Other propagation methods (less common):

Seed propagation: You can sow Rodgersia seeds in the fall, but germination can be slow and may require cold stratification, and seedlings may not always be true to the parent plant. 

Cuttings: Although possible, taking stem cuttings from Rodgersia is not generally recommended as they can be difficult to root.