I have had great success with my LA seeds except last year I planted them in ground too early and then we had a very dry summer. I should have watered them more as they didn't put on much growth. I was afraid they would not survive the Winter so poorly established so I potted them and put them under lights in my cool basement where they are looking good. My question is: will this pseudo growing season in my basement affect their potential bloom time? Do daylilies require a vernalization period to set buds?

Janet,
No daylilies do not require a vernalization period. At least from the posts I have read about people growing daylilies inside greenhouses, daylilies bloom without such a period.

Daylilies do not need vernalization. I wrote an article for a recent issue of the Daylily Journal about daylilies not needing to experience winter cold to flower.

But
If you grow daylilies inside over winter then their bloom time (the date when they start to flower) can be affected.

When there are no outside "forces", such as winter cold, to stop a daylily from growing it will simply flower after a certain amount of time and then flower again after more or less the same amount of time and then keep repeating its sequence of flowering and growing.

Daylilies that are grown inside during the winter will not flower at their normal time (of the year). Depending on how much light, water and fertilizer they are given while growing inside they may flower inside or earlier than normal when they are returned to the outside.

Some daylilies will stop growing if they experience sufficient winter cold (or possibly short day lengths or both). Some of those that do stop growing will start growing again without any problem when they are brought inside and given good growing conditions. However, some of those that stop growing will not start growing again (inside) until they experience summer-like temperatures, summer-like sunlight intensities and summer-like day lengths. In those cases I have found that it takes less than a week of those summer-like conditions to restart their growth.

I would like to draw your attention to Jamie Gossard's website. In the 2016 section, he has listed Swamp Dragon, and describes how dormant plants can dwindle when exposed to warm weather conditions without any cold. He has told me the same thing several times, as had Dan Trimmer. I have read other things that Jamie has posted about this issue comparing plants grown in Florida and a sibling that would only grow here, but I don't recall specifics at the moment. Here in my garden, I have that same issue with evergreen plants that don't have enough growing time and continually get frozen back. My dormant seedlings that have been started early will only reach a certain point the first year, but after a cold rest, they will often surge when the temps warm up again. Your seedlings might actually bloom this year, depending on how mature they are and if they are fully dormant or if they show any tendencies of being evergreen. Many of my more dormant plants begin to go down in August, and when they do that, they normally don't send up a scape. Plants that show evergreen tendencies will continue to grow, and you might see them begin to scape even in August or September. In my own garden, it is getting more common for plants to have reblooming genetics, and that will play a part in it as well.

I read the article that Maurice had in the Journal. There were a few parts of it that didn't align with what I have been told about dormant plants in the south, and I have no intentions of debating that issue. Part of it might be the degree of dormant behavior, or successive growing cycles compared to first bloom. I can visualize scientific data coming at me for posting this, but we have one guy telling us one thing, and many gardeners experiencing something different. In this situation, I think it will depend on how mature your plants are by May or June. If you have big vibrant plants, I would expect some scapes, but if the foliage is narrow and strappy, I wouldn't expect any.

Part 1 - Vernalization; Part 2 will be about Dormancy - they are not the same.

This post is specifically for @Deryll but also indirectly for everyone who has looked at, or will look at how plants grow or do not grow (flower, etc.) in natural conditions in different locations and tries to make conclusions about the actual biology of the daylilies.

Daylilies do not need to experience a period of cold temperatures to flower. That means they do not need vernalization.

That is specifically tested by growing daylilies and not letting them experience cold temperatures and seeing what happens. To understand what experiencing or not experiencing cold temperatures does to a daylily's biology one must change only one thing - that is the temperatures that the daylily experiences during the time that is effectively winter. Everything else that the daylily needs to grow, flower , etc. must be the same whether it experiences winter cold temperatures or does not experience them.

One of the things about temperature is that plants have optimum temperatures for growth, for flowering and possibly for many of their other biological functions. Those optimums can be different for every function (or not). As part of the effects of different temperatures on, for example, growth and flowering, there can be sub-optimal or negative effects of temperatures. One researcher, Arisumi, tested the effects of different temperatures on one daylily and found that continuous temperatures of 85F and 95F degrees visibly damaged the plants and completely prevented them from flowering. That (high temperatures being detrimental) is a typical finding for plant species. A temperature of 75F was optimal and temperatures of 65F and 55F, although not optimal, did not damage the daylilies but did slow their development and increase the length of time they needed before they flowered.

Growing and flowering daylilies in the South does not change only the cold temperatures that the daylilies may or may not experience. It also changes the high temperatures they experience and the length of time that they experience those high temperatures (and possibly many other important environmental factors, such as day or night lengths). Some aspects of Southern environments may have other effects on daylilies such as "summer dormancy" when they are grown in some Southern locations. That might be caused by above optimum high temperatures.

So, to examine whether daylilies need to experience cold temperatures to flower the daylilies must be grown in good conditions for growth and flowering except that only one thing is changed - the presence or absence of the cold temperature.

Growing a daylily, in say a Northern garden where it may grow well and flower well and comparing its growth there with how it grows and flowers in a Southern garden cannot tell us whether it does or does not need to be vernalized (experience a period of cold temperatures) because there are many other differences between the two growing environments (locations). Repeated high temperatures throughout the growing season (and year) is just one that may have negative effects on growth and flowering of daylilies in Southern gardens.

One of the things that we might predict if high temperatures (not the lack of winter cold temperatures) are a problem for some daylily cultivars when grown in Southern locations (apart from "summer dormancy" is that daylilies that apparently are well suited to Southern locations, for example because they rebloom multiple times in a year, may not be able to rebloom during (or for some time after) the hottest times of the year. It has been observed for a long time that many southern-bred reblooming daylilies frequently/consistently fail to rebloom during the hottest months in the South. [Continually hybridizing daylilies in locations with high temperatures and choosing parents from among the best rebloomers under those conditions will, with the passage of time (generations) produce daylilies that can rebloom in the hottest months and which have better and better rebloom at those times.]

The daylily cultivars that I tested for the article were the daylilies that a number of hybridizers had specifically personally observed to not flower in locations in Florida yet flower normally elsewhere or that had flowered for years in a location (Hawaii) but stopped flowering after a number of years in the same location (with the reason assumed to be the lack of sufficient cold in the later years). One of the cultivars was considered to need to be refrigerated to flower in some locations. When I test them all of the tested cultivars flowered without experiencing winter cold (actually temperatures anywhere near winter temperatures). They not only flowered without experiencing winter cold but they rebloomed repeatedly. As indicated in the article, researchers have found that the biology of vernalization (requiring winter cold to flower) does not affect rebloom. A different way of saying this is that any plant species that can rebloom cannot need to experience winter cold to flower. All daylilies can rebloom if they are given a long enough growing season at optimum temperatures. Once a daylily is mature (presumably large enough given the growing conditions) its vegetative meristem becomes a scape and at the same time a new vegetative meristem is produced which later becomes a scape when a new vegetative meristem is produced... this repeats as long as the environment is conducive for good plant growth - no winter cold is needed.

There are two things we know about daylilies - they do not need vernalization to flower (do not need to experience winter cold). And from Arisumi's research, high temperatures prevent some daylilies from flowering at all.

There is a simple requirement for learning about the effects of processes, such as vernalization, by comparing two groups of plants, that is, both groups of plants must experience everything identically except for the one factor (for example cold temperature) that is being tested. That cannot and is not done by comparing the same plant grown in the North versus grown in the South under normal garden conditions with none of the many other environmental factors that are different between the two locations being controlled and the same.

If a daylily does not flower in a location we cannot assume that it was because it did not experience winter cold if it also experienced different high temperatures from other locations where it does flower. The two locations will almost certainly have different climates with different weather. The growth and flowering of the daylily must be tested with only one thing changed - winter cold present or absent. A number of daylilies have been tested that did not flower in locations with mild winter temperatures. It is not the lack of winter temperatures that prevented those cultivars from flowering in those locations.

Part 2 Dormancy in daylily plants - winter cold.

Vernalization (winter cold for flowering) is different from winter cold for winter dormancy (or endodormancy).

Daylilies do not need to experience winter cold to flower. They rebloom repeatedly without experiencing cold. They do not need vernalization which is the term for needing to experience winter cold to flower.

A few daylily cultivars that I have brought inside over the years for winter have been winter dormant when I brought them in. When given warm temperatures, normal day lengths and reasonable light intensities they barely sprouted an inch or so and stopped growing. They sat like that for as long as I left them (several months).

Stout observed the same thing happening to some of the seedlings that he grew inside a greenhouse over winter. He called it "repressed growth". I call the growth "stalled". Stout found that some of the seedlings died. He also found that the repressed seedlings took a long time but did finally start to grow on their own. As well, if he provided some of the seedlings with weeks of cold they started to grow when they were returned to warm temperatures.

It is not surprising that daylilies with repressed/stalled growth over winter in a greenhouse might grow very poorly or die. Light intensities during winter are lower than during spring or summer. The length of the day is shorter during winter. So some daylilies may become dormant for winter and if they become and remain in repressed/stalled growth while being kept at warm temperatures with low light conditions they may grow very poorly or die and if they flower in their next growing season may do so poorly.

However, daylilies are not like many deciduous trees and shrubs that become dormant during winter. Many of those dormant trees and shrubs must experience sufficient winter cold or they do not grow well (if at all) when spring arrives. Daylilies do not actually need to experience winter cold to grow and flower perfectly normally.

If a daylily happens to become dormant during winter and does not start to grow normally when it is given warm temperatures and good light conditions (in other words, it is endodormant) then I have found that if it is given a long day (for example 18 hours or more of light, and the light is high intensity [good for growing vigorous plants] and the temperatures are warm (above 75F), then within a week or less the daylily stops being endodormant and grows normally. Such plants then grow and flower normally as expected if they had experienced a normal winter. In other words, daylilies do not need to experience winter cold to fulfil endodormancy requirements.

Daylilies do not need to experience winter dormancy and do not need to experience winter cold to break endodormancy or to fulfil the requirements of their winter dormancy.

Over the years I have brought many many daylily cultivars inside to grow and flower overt winter; less than a handful have shown winter endodormancy and needed warm temperatures, high light intensities and long day lengths to start into growth.

It is easy to understand that in some Southern locations daylily cultivars that become winter endodormant may not receive enough winter chilling to break their winter dormancy normally. By the time that the normal weather in such locations is warm enough, with long enough days, and high enough temperatures, such daylilies might have consumed too much of their stored reserves (needed to survive over winter and to produce new growth in the spring) and may then grow poorly and dwindle away (especially, if to add further to their poor growth, the summer temperatures in the location are above their optimum temperatures for growth and thus produce poor growth.

All daylilies grown in my zone are forced to be dormant simply by the very cold, long winter months. But I have wondered if the variations of length of daylight here might effect how well they bloom.

Winter solstice here has a day length of 9 hours and zero minutes, whereas our summer solstice tops out at 15 hours and 22 minutes of daylight.

Would the decreasing length of daylight hours here in the north trigger or shorten daylily blooming to any significant degree or would that be more contingent on declining temperatures?

@adknative It would be more contingent on the lower temperatures.

Arisumi (a biologist) grew daylilies at five constant temperatures in a greenhouse. He took groups of plants into the greenhouse at monthly intervals from November to February. The daylilies were only able to flower normally within the length of the experiment at 75F (100% flowered 24/24). At 65F the daylilies started to flower not long after the end of the experiment. At 55F the daylilies would have (probably) flowered considerably after the end of the experiment. At 85F and 95F the daylilies started to grow normally and then visibly suffered. None of the daylilies at 95F flowered and only four out of twenty four of the daylilies flowered at 85F.

Arisumi wrote "From these bloom dates it can be reasoned that at 65° it would have required at least 170 days to first flower for plants forced in November and 140 days for those forced in December" (after the end of the experiment).

From Aisumi's statement we can assume that the difference in the length of the daylight and its intensity between November and December caused a 30 day difference in the time to the start of flowering (at 65F) at Beltsville, Maryland.

The daylilies that were started to be forced in November needed 122 to 146 days before they opened their first flower during the experiment. Those started to be forced in December needed 101 to 117 days and those started to be forced in January needed 92 to 99 days (during the experiment).

Those differences were caused by the differences in the length of the days and the intensity of light during the growing periods in late autumn and winter.

The effect of shorter days (duration) and lower intensities of sunlight during the autumn and winter are very important factors for the growth of daylilies that are in greenhouses during that time. Neither of those factors are sufficient for "normal" growth and flowering of daylilies. That is particularly so for the winter period. So additional light from normal or grow lights during winter will produce better growth and flowering. That is particularly so in the more northern locations where day lengths are shorter and sunlight intensities are lower.

The temperatures above a daylily cultivar's optimum have negative effects on its growth and flowering (the higher the more negative). Different daylily cultivars may have different optimum temperatures. The optimum temperatures for the growth of different plant characteristics may be different, for example daylily leaves versus flower bud growth.

Arisumi wrote "At 85° and 95° the plants grew rapidly during the first 3 to 4 weeks and then became progressively chlorotic and the older leaves dried prematurely." He also wrote "At 85° most of the flower buds were blasted and only a few misshapen flowers bloomed. The scapes were weak and about half the size of those formed at 75°."

Bear in mind that these were constant temperatures.

@Deryll Let's look at 'Swamp Dragon' specifically.

This is from https://heavenlygardens.com/im...
"Flowers of Swamp Dragon are raspberry purple above appliquéd patterned green throat. Selected in Florida at the Spacecoast garden, hybridized by John Kinnebrew. In the seedling patch it was wonderful the first year. However it was going down hill by the next spring, because it was so hard dormant. Most all dormants do not perform well in the Spacecoast garden. I brought it back to Ohio in the fall and planted it outside without mulching. It grew and performed super good."

First - very important - dormancy is biologically different from vernalization.

To be even more specific endodormancy is different from ecodormancy. A plant is ecodormant when it simply stops growing. It may have formed a bud or it may not. To start growing again it just needs to experience good growing conditions; it does not need to experience winter cold for example.

Endodormancy can be different - a plant may need to experience a certain environment or environments to break the endodormancy and have its buds sprout.

From the description of the events, it is clear that 'Swamp Dragon' is an endodormant daylily. If it experiences its required environmental signals to become endodormant it will become endodormant. In that case it can start to grow again when its requirements for fulfilling its endodormancy are met. If those requirements are not met in a timely manner then it will most likely show Stout's "repressed growth" (my stalled growth) for a sufficient length of time that its growth suffers in the climate conditions where it was grown in Florida.

That does not mean that 'Swamp Dragon' needs to experience (must experience) endodormancy to grow and flower well. Nor does it mean that if it has become endodormant that it needs (must experience) winter cold of sufficient duration to grow and flower well.

An endodormant daylily can have its endodormancy "broken" by a week or less of warm temperatures, high light intensities (normal summer) and long day lengths (normal summer). It will then go on to flower and grow normally.

OR

A daylily that is able to become endodormant (when it experiences its necessary conditions to do so) actually grows and flowers normally if it never is allowed to experience the conditions that will make it endodormant.

If a daylily that can become endodormant does in fact become endodormant then if that endodormancy is not broken appropriately the daylily may suffer severely. Stout found that a long time ago.

What I have found is that most daylilies do not become endodormant. That if such daylilies are not allowed to become endodormant they grow and flower normally. If they are allowed to become endodormant then if that endodormancy is broken (and cold temperatures are not necessary to do that) it will grow and flower normally.

If a daylily that is capable of becoming endodormant is grown in conditions that cause it to become endodormant then leaving it to come out of its endodormancy because of a lengthy lapse of time may harm its growth and flowering (confirming Stout's observations). However, artificially breaking its endodormancy (with a short period of high light, long days and warm temperatures (cold not needed) allows it to grow and flower normally.

Daylilies, even endodormant daylilies, do not need (= do not have a mandatory requirement) to experience winter cold to grow and flower normally. That is a statement about the biology of daylilies. It does not affect the problem(s) associated with letting a daylily with the ability to become endodormant actually become endodormant and keeping that daylily in conditions where it cannot grow well until its endodormancy is naturally broken after a long time. That is 'Swamp Dragon' in Florida.

If anyone is willing to send me a plant of 'Swamp Dragon' (to Canada - phytosanitary inspection & certificate required) I will gladly test its ability to grow, flower and rebloom normally without ever experiencing winter cold. I am 100% confident that it will do so.

I KNEW this was coming! Don't shoot the messenger! You need to take this up with people who are experienced growers in the southern states. People who have repeatedly told me that plants such as Neon Flamingo, Heavenly Angel Ice or South Seas will succumb after trying to grow over a couple years in southern gardens, and they do not bloom there. There is a host of other northern dormant plants in the same position. If you need plants to experiment on, they are sold everywhere.

In the situation for the lady above, it really wasn't a case of vernalization, but whether her plants would be mature enough to send up scapes. I have no idea how mature they are. I know her question was about vernalization, but I think "maturity" is a better fit.

I really don't need a class on this stuff, and this takes it seriously much further than we need for an informal question. To be honest, it was waaaay over the top and I only glanced at parts of it. If you have discussions with people like Jamie Gossard, Dan Trimmer, Guy Pierce, Tim Bell or Ted Petit, we would certainly like to know how it turns out....

Well the only one of the three daylilies mentioned by Deryll that I had for years that thrived and multiplied like a weed was 'South Seas.' Every one I ever spoke to in this area(zone 8b) said it was a stand out performer. I had it for years, but it seemed to have little resistance to the weed killer I accidentally sprayed it and many others with (most of them also died).I have only had 'Heavenly Angel Ice' for one blooming season( and it had a great one season) so can't comment on its longer term performance yet. I have never grown 'Neon Flamingo'.

So many variables!! Hard to articulate what might or might not happen. I have read with interest many "Plant of the Day" forums. Apart from the diversity of environments in the US I see lots of varied planting locations wrt shade, nutrition, root competition.

I can say that some cultivars DO NOT NEED COLD SPELLS to bloom. It is years since we have had a temperature of less than 40 F. In our early Summer I had some flower continuously for up to 3 months. In Spring we had several days over 90 F but this patch gets some shade. I think this is Tuscawilla Snowdrift. It can be light yellow or pink but is mostly near white and huge.

Likewise TUFF STUFF surviving and blooming lots.
In my experience the high temperatures here (plus maybe the months of Extreme UV) do make daylilies suffer. Our drought and deluge climate kills the roots of many plants. But some daylilies are astonishingly tough survivors. After a few years of extreme neglect, daylilies I thought I'd lost reappeared. 2 of these even bloomed. CONGO CORAL was a few blades of green in a small pot. A month later, in bright shade, it had 2 blooms.

Similarly, in early Spring I identified STAR OF FANTASY, a tiny plant in a large black pot. But it bloomed several times in Spring and is about to rebloom after 2 weeks of 90 F days. It is in bright shade. Direct sun cooks plants in dark pots. My pics seem to have vanished sorry.

We also have pretty constant high humidity, often above 80% at night. In spite of a lot of rain in the last year, the previous dry high temps seem to have killed back rust on most of my hems.

Lastly, many so called deciduous hems are evergreen or SEv here and do well in out subtropical climate. GlenI used to make posts to that effect about some of his hems.

Janet, regarding growing your daylilies inside, I see you have provided lighting extra to the needs of people?? But I wonder about the humidity. Most plants, even some succulents find inside houses has air too dry to thrive. Anything that grows well inside here often becomes a weed if planted outside.

Also, Maurice's comment about reblooming plants is interesting to me. Here, it is probably now a few degrees too warm to flower any bearded iris (although they grow well enough). But a few years ago I had a few flower, mostly known rebloomers or very early ones, but even 'Return To Camelot' which was in a pot, (and has since rotted). When I first grew daylilies here I would often see bloom at any time of year. I will try and make some posts about rust resistant plants in the next few months.

Also here is a NOID I call Currumbin Creek Red. After months of sitting in water, in part shade, this proliferation from early last year flowered twice, and to my astonishment set a bee pod.

@Deryll
There is no need to contact more hybridizers for more examples of cultivars that have problems growing and flowering in the South. Nor is there any need for more discussions with hybridizers who believed (or still believe) that some daylilies have a mandatory requirement for winter chilling. I did that originally. That is how I chose the particular cultivars that I would test and write about in the article in the Daylily Journal.

Before choosing which cultivars to test I found hybridizers who had written about daylilies having problems in the south and who believed that the problems were caused by winter dormancy (endodormancy) and the lack of vernalization. Some of those hybridizers were from Florida and some were from other similar locations. They had personal experience with the problems associated with growing daylilies in the South in climates with mild winters with little or no possibility of "winter chilling". At least one had grown the same cultivars in more Northern locations where they grew and flowered well and then moved the same cultivars to Florida and found that they did not. Entire breeding lines of that hybridizer had the problem. In another example, cultivars identified by a Florida hybridizer as having problems in the South were refrigerated by another hybridizer based further North ("winterized") and then sent to the Florida hybridizer who would then hybridize with them when they flowered for him.

I chose the cultivars that I tested in discussions with those hybridizers who had personal experience of the problems. The names of three of the hybridizers that I contacted are mentioned in the article. Many hybridizers in the past have believed that the problems associated with growing and flowering daylilies in Florida and similar Southern locations are caused by dormancy and vernalization. There was no need to contact them all for the names of all the cultivars that they personally had identified as having those sorts of problems. Only a sample of such cultivars need to be tested. That is what I tested. The hybridizers were asked to name the cultivars with problems and I used those cultivars.

Perhaps it would also be useful if I explain an important aspect of having articles that contain anything to do with science or biology published in the Daylily Journal.

The American Hemerocallis Society has a committee (Scientific Studies - SSC) that is made up of some hybridizers, some scientists - some retired, and otherwise knowledgeable society members. The SSC must approve all articles that involve any aspect of the biology of daylilies (science). The members of the committee read submitted articles and then may question any and all aspects, conclusions, methods, assumptions, etc. in the article. The author answers those questions and basically must convince the committee of the correctness of everything about and in the article. You can rest assured that my article was discussed with the Scientific Studies committee. It had to approve the final article otherwise the article would not have been published.

I read the article in the Journal. Stella, Happy Returns, Sandra Elizabeth etc... I am positive that your findings are accurate, and I am sure that the committee checked it before they printed it.

I am only saying that some big reputable growers might have a different opinion based on their experiences. Perhaps those plants were from the entire breeding line of a certain hybridizer..... or perhaps real life experiences might not compare with clinical studies in a laboratory.... I really don't know, and since I don't live in those places, I can't speculate.

I do recall that Pluto used to be considered a planet, and that was published also. With more research, apparently it wasn't quite accurate....

@Deryll

Just to confirm, you do understand that according to my tests all that is necessary to successfully grow plants like 'Swamp Dragon' in locations in Southern Florida where they dwindle away, is to wait until they have gone dormant. Then to place an ordinary 800 lumen light a couple of inches away from the crown of the plant and leave it switched on for say 18 to 20 hours of each day. Within a week (approximately) the "treatment" will have broken the dormancy and 'Swamp Dragon' will then grow and flower normally.

Of course, that is easier if such a plant is grown in a pot since the pot can be moved inside for the treatment. It is also easier if the light is simply left on continuously (24 hours per day).

That is, even those daylilies, like 'Swamp Dragon' do not have a mandatory need to experience cold.

P.S. Some years ago, two fans of 'Megatron' arrived here dormant too late in the year to plant outside. I potted them separately and treated them as above. They broke their dormancy and grew normally both inside under the lights that winter and the rest of the year outside after winter had ended.

Megatron (Gossard, 2006) height 30 inches (76 cm), bloom 10.5 inches (27 cm), season M, Rebloom, Dormant, Tetraploid, Fragrant, 18 buds, 3 branches, Red with darker watermark above green throat. (((Court Magician × Galaxy Rose) × Red Hurricane) × Webster's Pink Wonder)

Let's for completeness assume that the problem with 'Swamp Dragon' in Florida has nothing to do with dormancy.

Then it may be that the problem is far simpler and one that may affect every plant of any species.

Plants have three important temperatures for all their basic functions. Those temperatures may be different for each function. They are called cardinal temperatures. The three cardinal temperatures using plant growth as the example, are the minimum temperature (below which the plant does not grow), the optimum temperature (at which the plant grows the fastest say) and the maximum temperature (above which plant growth suffers and the plant may be injured, etc). Each daylily may have different cardinal temperatures. Daylilies that have been hybridized in a particular location for consecutive generations may be "naturally selected" to have cardinal temperatures suited to their location.

Then an alternative possibility for why plants such as 'Swamp Dragon' may suffer when grown in locations such as Florida is that their optimum and maximum temperatures are lower than those of other daylilies that do not suffer when grown in Florida. This assumes that the temperatures in Florida are high enough to be above the optimum for some daylily cultivars while the temperatures in Galloway, Ohio are not.

Then there is always the possibility that both factors affect some cultivars.

P.S. There are no clinical studies in a laboratory here. The plants are simply grown in a pot and moved inside the house to be grown under inexpensive grow lights at the necessary times. There is no sophisticated or very expensive equipment. The "tests"/observations are very simple. Anyone can repeat them and I encourage anyone who has doubts to do so. If anyone has questions please ask me.

Long ago Moldovan [Ohio] and Munson [Florida] swapped introductions. They were both unhappy with the way their introductions grew and flowered in the other location. They introduced each other's daylilies into their breeding populations to produce daylilies that were better adapted to the other (than their own) conditions. It has never been unusual for a plant that was hybridized in one location to do poorly in a location with a noticeably different set of conditions. Dormancy or the lack of it need not be the cause.

It seems to me that some daylilies rot more easily than others. I recall a grower in South Australia saying Scarlet Orbit succumbed easily to root rot. Even some cold spells did not save it. I've seen comments in NGA forums about particular cultivars and their offspring being prone to root rot. It doesn't surprise me that some die away in hot places, especially if they are hot and often wet. Heaps of fungi and bacteria live in tropical soils. Some can cause fatal sickness in humans eg Melioidosis

I recall realising when I was 9 years old that roots were super important parts of plants. Many plants can be cut off to ground level and regrow (not conifers). But poor drainage kills many plants, and once they start, rot problems are hard to fix. Drought is tough on hems, but they often come back if conditions are ideal. eg My Congo Coral and Star Of Fantasy.