To propagate Carex, the most common method is by division, which is best done in early spring when the plant is actively growing, by carefully digging up the clump and separating it into smaller sections with roots and foliage attached, then replanting each section individually; you can also try propagating Carex from seed, but this can be more challenging and often requires cold stratification to improve germination rates. 

Key points about propagating Carex by division:

Timing: Early spring is the ideal time to divide Carex. 

Preparation: Water the plant thoroughly a day before dividing to make the roots easier to separate. 

Digging: Carefully dig around the plant to loosen the soil and lift the entire clump. 

Dividing: Use a sharp knife or your hands to separate the clump into smaller sections, ensuring each section has healthy roots and shoots. 

Repotting: Plant the divided sections immediately in prepared soil, ensuring they are planted at the same depth as the original plant. 

Propagating Carex from seed:

Stratification: Most Carex seeds require cold stratification, which means exposing them to a period of cold, moist conditions to stimulate germination. 

Sowing: Sow seeds in a seed tray with a well-draining potting mix, lightly covering them with soil. 

Germination conditions: Keep the seed tray in a cool, shaded area and maintain consistent moisture levels until germination occurs. 

Important considerations:

Choose the right variety: Different Carex varieties may have slightly different propagation requirements. 

Check for invasive tendencies: Some Carex varieties can spread aggressively, so be sure to select a suitable type for your garden. 

Soil conditions: Carex generally prefers moist, well-drained soil.