Daylily flowers provide a rainbow spectrum of color that bloom over a long period and the plants offer sizes that vary from small feathery clumps to large, fans of green foliage. Because of these differences in color and size, I've found that I occasionally plant with an aesthetic vision in mind but when the plants mature I want to adjust their positions and multiply the plants I especially like. Easy propagation is a godsend in those situations.
Collecting and sowing seeds from daylilies in your garden is a crapshoot. The daylilies you grow are probably hybrids. They won't grow true to the parent plant when grown from seed because it is a cross of other varieties. If you have multiple varieties of daylilies in your bed, there is no telling which flower pollinated another. With varied hybrid parents or different hybrid cultivars involved with pollination, the resulting seed will grow into an unknown, future plant.
It can take three years for a seed to germinate and grow into a plant that flowers. After all that time, be ready for a surprise when the plant produces that first bloom. There's no way to tell what color or size it will be ahead of time, but with so many positive attributes that daylilies offer, it will probably be a nice surprise.
If you don't plan to save the seeds, remove the seed pods. Plants that produce seeds will usually have fewer flowers the next year. Since one of the reasons you grow daylilies is for the flowers, there's no reason to intentionally restrict future flowers.
The second form of daylily propagation is division. Large clumps of daylilies can be divided easily and this is the preferred method of propagation when you want your plant to have the same size and color as the parent. It also will produce flowers faster. Each plant grows into a clump that will be ready for division about every three or four years. Undivided plants will begin to produce fewer flowers so you're doing yourself and the plant a favor by dividing regularly.
Daylilies can be divided in spring or fall. The plants that are divided in spring grow quickly afterward, but they seldom bloom in that first year. Primarily for that reason, I prefer to propagate in the fall. Fall propagated plants will almost always bloom the next year. You should wait until after the plant flowers, but dividing and transplanting the divisions should happen at least six weeks before the ground freezes.
Brush or wash away the soil attached to the roots to expose them. Many daylily roots are enlarged and tuberous. This is where the plant stores food and water and enables the divisions to grow well after transplanting. The more roots in the division, the better chance for survival of the transplant.
You'll be able to see how the fans form distinctive and individual sections where they attach to the roots. Each of these sections can be pulled apart from the others. I find it easiest to begin by lightly shaking the plant and seeing where it begins to separate naturally. Then I gently pull apart the plant into two divisions. Often each of those divisions can be pulled into two or three additional divisions.
Divisions should have three or four fans with stout roots attached. These will establish more quickly, grow into good clumps, and flower within a year. You can also divide to the point where you have individual fans with just five or six slender leaves. These individual fans can be transplanted with no problems but may take a few seasons before they reach a size where they will begin flowering.
Some old, large clumps may have roots that are so extensive in the center that it is virtually a solid mass. These clumps may need to be cut apart with a garden knife or sharp spade. Try to cut in such a way that you keep the integrity of the individual fans intact.
The divisions should be transplanted soon after digging up so the roots don't dry out. On each division, cut the leaves so that only five or six inches remain above the crown. This reduces water loss and stress. The crown is the part where the leaves and roots meet and is usually cream colored. Place the plant in the hole with the crown about one inch below the surface level.
After the divisions are in the ground, water thoroughly. Keep the soil moist until the ground freezes. Use a few inches of mulch to moderate soil moisture and temperature levels. Mulch also reduces weeds and highlights the beauty of the plants.
In time daylilies will form dense mats of plants. By dividing them you can keep the plants under control and looking their best. Propagation is a great way to expand their wonder to other areas. And don't forget that you may have many gardener friends who would love to have some of your extra divisions.