Lifting and dividing the crowns and roots should only be done every 6 years or when the crowns lift out of the soil.
Seeds should be sown in the autumn right after they are harvested.
Seeds can be placed in trays or pots of planting medium and placed in a cold frame. Germination is very slow and it can take up to 12 months.
They are not too fond of being uprooted but it can be done. Seeding is your best chance at propagation. Here is a link on more info;