Planting and Care of New Divisions
To plant a daylily, dig a shallow hole that the roots will fit in, form a mound in the center of the hole from soil, fan out the daylily roots and place them over the mound, then fill in with dirt. The crown should just be at ground level, perhaps a touch above in the south and an inch or so below in the north. I move daylilies here any time the ground is not frozen and the cultivars that are hardy here tend to have no problem with that and do fine here in my zone 6 garden. You may want to add a bit of water and fertilize (especially time released) when you plant. You can also add some mulch of some type to help retain moisture.
In colder zones, for those planted late in the year or when there is danger of frost, you can use a rock or heavy object to weight down the division to keep it from heaving out of the ground, and I would also recommend some type of mulch. I find that heaving from freezing is the main thing that kills daylilies newly planted in the fall in cold-winter areas. There are some daylilies though that are tender and won't survive cold winters well. These should only be planted in the spring in cold climates to get them somewhat established by winter. Even at that some won't survive.
Conversely, there are daylilies that do not survive well in the south. These are typically plants registered as 'dormant'. Some plants seem to require a rest period of cold weather and the continuos warmth in the deep south can cause some of these daylilies to fail, withering away over time. Talk to people growing in your zone to find out what does or doesn't work in terms of tenderness. Not all evergreen plants are tender nor do all thrive in the deep south, and not all dormant plants are hardy and some do well in the south, so you really have to do some research on this. You can find a lot of daylily growers on Facebook. I bet you find some in your area on there and they can get you in touch with local groups. As well, you can go to the American Hemerocallis Society website and check for groups in your area (called regions at AHS website).
When growing daylilies, one must always remember that the registry statistics (such as scape height, branch and bud counts, flower size, etc.) are somewhat variable even on an established clump, and especially so with new divisions, of most daylily cultivars. The environment can also cause variations.
When you receive a daylily division, that division has been dug up and the roots have been disturbed. Some are cut off from solid crowns, while others separate into fans without requiring cutting. Regardless of which method is required to make the division, this causes stress. The plant itself may be a division from an established clump, a division that has been lined out or potted for a few months or a year (or a further division from such a division) or even a division that has been sitting on a shelf somewhere for any number of months in storage (think those packaged daylily roots you see in box stores in spring and fall...). All of these conditions create various levels of stress and your new plant will have to become established in your garden before you can expect to see the statistics of a mature clump. Even potted daylilies purchased at garden centers will have some stress when taken out of the pot and replanted into your garden, as the roots are still going to be disturbed and the plant likely isn't a mature clump.
In my experience it takes three full years of growth in the garden from planting for the vast majority of daylilies to mature, become fully established and reach 'clump strength', which is when you can expect to see the plant show its fullest performance in your garden. However, bad conditions in the environment can cause there to be situations where even a three year planting doesn't live up to its fullest potential.
You should also be aware that the statistics of a given plant are based upon the performance in the hybridizer's garden. If you have vastly different conditions, you may never see the stats of the registration. A good example is branching, which may be remarkable in zone 9 or in extremely fertile and amended (high input) conditions, but may be drastically less impressive the further north one goes from zone 9, or in a garden with less-rich soil conditions. I don't consider this to be a deception on the part of the grower in zone 9, I simply know that their conditions are not my conditions and I can't expect to see the performance statistics they see. You have to be realistic and understand that daylilies are highly variable and what they do in my garden, they may not do in your garden, and vice-versa.
In general, a first year daylily should put up at least one scape, if the division you received was of mature, blooming sized fans. The size of fan required for a given cultivar to bloom can vary wildly between different cultivars. Minis obviously are mature with a much smaller fan and many spider and UF types have smaller fans at maturity, while something like a giant tetraploid such as Sears Tower may make quite large fans when mature. However, some daylilies do not bloom at all in the first year of division and that doesn't make them terrible plants. It isn't ideal, but it happens and it shouldn't mark a plant out. It must be stressed though that first year scapes are not going to show the traits of the scapes on mature plants. They are generally shorter than normal, with usually reduced branch and bud counts. It isn't unusual for a first year scape to have no branches and just a few buds.
If you have a first year double fan division that does better than that on its first year, or shows near-mature stats, take note as that is exceptional. It is highly desirable and such plants can greatly benefit a breeding program, but it is the exception, not the rule. Further, in the first year it is not uncommon to see deformed and spotty blooms as well as some (possibly significant) bud death and drop, especially if a hot, dry spell coincides with scape emergence or if there are significant plant predators such as aphids or thrips.
Some first year plants may not increase in fan count, while others do. Plants with good increase in the first year are often desirable, but they can also end up 'going to grass' and requiring division within a couple of years to be refreshed. Plants that 'go to grass' often give very poor performance over time as they crowd themselves out. The most desirable plants to me are those that multiply quickly, do not go to grass and can remain a functional mature clump for many years without requiring division, but that also spring back fast when they are divided. Again, the exception, and not the rule.
Generally in the second year you will see blooms, and if you saw blooms in the first year (no matter how few) you will tend to see an improvement, though often they still won't reach the registry stats at that time. Problems from the first year should begin to be less extreme, IF the plant isn't prone to those problems even on an established clump and in a perfect year. For instance, the blooms may be more properly formed and less spotty, unless they are simply prone to be spotty, deformed, etc (and these do occur, especially where resistance to insect predators is low, etc.).
If you have poor environmental conditions in the second year, you may see more problems, but do bear in mind that this may be more environmentally predicated than typical. However, plants that give a good show in their second year (and especially if they gave a good showing in their first year) are to be noted! Take special note of those that give a good show in their second year even if there are environmental problems! Again, they are not the rule and are the exception, but they occur and are very important to use both as reliable back-bone plants in the garden and to improve plant traits in breeding programs. There will be some few plants that don't bloom in their second year. That is a strike against them for me, though I do take environment into consideration, but they still get 'put on notice' in my notes when that happens.
In the third year, a good daylily will be well-established and should give a beautiful show. Again, environmental conditions may cause problems, so you must take that into consideration. By this time most daylily plants will be settled in, their root systems will be established and the plant should be mature and have shown some fan increase each year. It should give you a view of what it can do in your garden at 'clump strength'. However, there are plants that may have never increased or even bloom by their third year. I never retain such a plant, but some breeders may if there are genetic traits there they feel they must have in their program.
If there are environmental issues in the third year, you may still see problems, such as spotting of flowers or decreases buds/branches, but you should see this as a general trend throughout much of the garden, and not on just the one plant. If it is particularly noticeable on the three year plant when many others do not show the problem, it is likely to be a problem specific to that plant.
It must be remembered though that there are situations where a plant will never show its registry stats for you. Things bred in Florida almost never show the scape height, branching or bud count they are registered with here in my garden. Things bred in greenhouses in the north may show the same problems unless they have been trialed outside before introduction (and stat-gathering was done outside after a winter or three in the ground). However, I don't always expect them to show their full potential here either, really. There are no other species of plants I could expect to bring up from Florida and expect to perform as well here (most wouldn't even live) as they do there. A dose of realism about what is actually possible goes a long way toward not being disappointed.
Over time, you will notice trends in your garden and you will get some idea of what to expect. As well, you will form ideas of what is or isn't acceptable to you. I want you to be prepared with realistic information so that you won't be disappointed by your new plants, but I have to say, some plants can be disappointing. It happens. That's life. Not everything can reach its full potential everywhere. This can vary from zone to zone, region to region and even garden to garden, but you can often find a good consensus on plants that have been grown in many gardens for several years.
However, it is also important to have some idea of the three-year cycle that a plant requires to become fully established and to understand that you won't likely see the full show until the third year (if the weather/climate/environment is cooperative). Breeders can breed from a plant as soon as they get viable pollen and/or viable pods. Your plant is probably going to be fairly pretty in flower from the get-go and many daylilies can give a nice little show even in their first year, but you need time to see what they are really capable of.
Exceptional plants are those that give good performance even under stress. They are rare. A great example is Frans Hals. An exceptional plant may show better performance under stress than you might reasonably expect. Such plants become obvious over time if you are paying attention and taking a few notes. A tiny minority of exceptional plants may even be 'super-exceptional' and give great performance even when the environment is causing problems. If you are breeding daylilies, please (please, please) note and use such plants. They can greatly improve the performance of your seedlings and your program in general.
I can't stress enough that plant traits are more than just branching or bud count, and if you will pay attention to your plants year-round, noting their performance under every adverse condition, and noting those that do the best under each of those adverse conditions, you can choose base plants for your program that can be used to improve the plant traits on poor performers that may have very desirable flower traits. Crossing less vigorous performers with advanced traits to your most exceptional plants can allow you to breed and select over time for plants with the advanced flower trait and improved plant performance. Such breeding has traditionally been a part of 'plant improvement' in most branches of horticulture.
Once you have your divisions planted, you may wish to water some in the first year to help the plant establish, especially if you have a dry year. You may add a little fertilizer as well. By the second year, a strong daylily shouldn't require either, though neither will hurt and if you choose to water and/or fertilize, you will see better performance. The registry stats are more often than not from gardens with improved soil, as well as watering and fertilizing programs. The use of additive water and nutrients can and will improve performance on all levels, though there are daylilies that will perform at their registry stats without any additive inputs. Again, those are exceptional plants and should be noted when encountered. They have something special. Those special traits should be perpetuated where they are heritable.
While daylilies are touted as "carefree" plants, that is only true for some of the many available cultivars. Many do require some care to give a good show and some may be difficult even in the best care with high inputs. Be careful to take your time and do some research before buying based on pretty pictures. You may not be capable of giving that plant what it needs to make that flower. There are many well-known daylilies that have been grown all over the country and a lot is known about their performance abilities. Do some research when looking to buy and talk to people who grow daylilies in conditions similar to yours. That, along with being aware of the three year cycle and being realistic about what any daylily can do, will potentially save you some stress, loss and heartache, leading to a happy and fulfilling daylily growing experience.
Good luck and happy gardening!