Dividing the daylily clumps by digging then pulling or cutting apart the clump is the most common form of daylily propagation. Division is relatively easy to do, plant survival is excellent and the resulting plants are identical. Daylilies only need to be divided every three -five years or so. If your blooms start to decrease, its probably time to divide. You can spread them around your gaden or give them to friends. Simply use your shovel to carefully uproot a large clump of daylilies. Large clumps can be VERY heavy- don't wiat too long to divide. I often wish that I hadn't waited that extra year... Once this is completed, rinse the soil from the roots. This will help you distinguish where one plant begins, and another ends. Gently pull and twist the fans apart, you can use a knife to carefully separate each division. I prefer to insert two large scredrivers through the clump and gently (sometimes not so much) pry and shake the clump into pieces. If you do damage some roots, it is helpful to allow the roots to dry so the wound can 'scab' over before planting to prevent fungal infection.These plants are hardy, you may lose a few fans if particularly difficult to divide. The US National Arboretum has a great page on dividing daylilies here The best time to divide daylililes is during spring or late summer, although, they can be divided anytime in the summer.
Seed propagation can start with seed collected from the capsules found on the scapes or from seed produced from selected crosses of different cultivars. Seed is collected as the capsule matures, drys, and is beginning to split at the tip. We harvest the seeds and allow to dry for 1-3 days. Place the seeds in brown paper coin envelopes and store in the refrigerator. Most seeds will remain viable 1 to 4 years. Seeds from dormant daylilies require the refrigeration (cold stratification). Seeds from evergreen parents can be, directly sown or, handled and stored the same as described above for seeds from dormant parents.
To cross two daylilies simply pull the stamen from one flower and apply it to the pistil of another(see photo), mark the flower that you used for identification later. This plant is know as the pod parent, the other is the pollen parent. Hopefully, the pollen will take and a pod will form. Handle the seeds as above and in a couple years, you will have plants different from either parent and from each other. It can take evaluating thousands of plants to find one that is worth introducing. Keeping careful records of each cross is also critical to successful hybridizing.
Proliferations are small plants that grow on the scapes of daylilies. Proliferations can be cut from the scape and stuck in a well-drained media. It is helpful to leave about an inch or two of the scape below the proliferation to inset into the media. This will help stabilize the proliferation on the media. The proliferations will expand roots out into the media in approximately a week.