To propagate Hardy Gloxinia (Incarvillea delavayi), you can most easily do so by dividing the plant clumps in early spring or fall or by sowing seeds indoors in late winter or early spring; both methods are considered effective for propagating this plant. 

Key points about propagating Hardy Gloxinia:

Division:

Dig up the established plant in early spring or fall. 

Carefully separate the root clumps, ensuring each division has healthy roots and shoots.  Re-pot the divided sections in fresh soil. 

Seed Propagation:

Sow seeds indoors in a well-draining seed starting mix. 

Lightly cover the seeds with soil and keep the soil moist.  Provide warm temperatures (around 65°F) for germination.  Once seedlings have developed a few sets of leaves, transplant them outdoors after the last frost.