@florange, can we walk through what happens to dormants in your garden?

When do they arrive?

After they arrive presumably they grow a crop of new leaves - what happens to those leaves? When do the leaves die? What happens to the plants after their first set of leaves dies? What happens to them during the summer and autumn? How does their growth compare that first year to other new plants that have arrived in your garden and are not registered dormants?

What happens to them during the winter? If they survive their first winter and sprout what does that new crop of leaves look like? How does it grow?

Do both you and your friend treat the foliage of your daylilies in the same way - you both remove dead leaves or you both leave them? Do you both weed equally often; do you both mulch in the same way or neither of you mulch, etc.

OK, dinner is over. I'll try to answer what I can. I have to say, first, that I am trained as an analyst and when I make statements I try to say only what I think has been proven. Second, both gardens (mine and my friend's) are private gardens and we have not conducted controlled experiments. We are both experienced daylily growers. She has a couple thousand because she and her husband hybridize. As far as I know they have not registered any daylilies. My garden contains 80 plants--it's a small beach lot. I live in a very limited micro climate. My garden is on Daytona's barrier island and is located at the narrowest width (2.5 blocks wide) with the ocean on one side and the Intercoastal Waterway on the other. Collecting data from Daytona would not yield any information about this location.

1) & 2) My friend measures her air and soil temperatures herself. So do I. We use the same thermometer because I found it to be very useful--shows high and low temperatures for the day. I recommended it to her. I use a probe to measure soil temperatures at the beginning of the month--usually in late winter/early spring. Do also measure the soil later in the year just for yucks. I don't know her routine.

3) I have known my friend for 10 years (met her at a daylily function). We talk every 7-10 days and each and every time we talk weather and daylilies and then move to other subjects. As the sun rises and falls, her air temperatures exceed 80 degrees about 10 (and sometimes more) days before we get those temperatures. And in late fall her air temperatures are usually 10-15 degrees higher. She is inland where it does get hot and stays that way!

4) My friend lives 4 hr from me and I don't see her often. I do tell her the growing conditions I used for any plants I send her. Her garden is mostly sun, so I assume her daylilies are in full sun/part shade just like mine.

5) Because of this micro climate, I don't think data is available to yield reliable information.

How should I say this. I research parentage of the daylilies I buy. If they have dormant "parents" or "grandparents" I no longer buy them. It's a waste of money. I've planted some dormants here. They never go down. Their foliage stays 2 or 3" above the ground through winter and they are later to start new growth than the evergreen daylilies that flourish here. The dormants will last 2-3 years, starting out fine when they arrive and then getting smaller each year until they turn into grass. I always purchase daylilies in the fall--usually October when temperatures start going down. The plants come with full foliage and as the days shorten (it usually doesn't get below 70 until after December) their foliage shrinks down and stays that way until late March, early April. I have a few out there now going through that. They seem to be fine that first year. Most keep foliage during the summer although some do go through summer dormancy. When they do that, their foliage never grains full height when they come out of it. Usually after the first year, budcounts decline, rebloom goes away and the plant starts it's slow death. I would say the dormants NEVER look as good as the evergreens--my EV's are bold, tall and dark green even in the depth of winter. When early spring occurs, the new dormants start to grow, but not as lush as the EV's. Their blooms are puny compared to EV's. The EV's will always out grow and out bloom dormants IN MY GARDEN.

I remove dead leaves. Don't know what friend does--too many plants to manage. We both grow in boxes (sand is not conducive to good performing daylilies). Weeds aren't a big problem in boxes. We both keep the boxes clean and never, ever mulch. We both get a lot of annual rain fall and mulched daylilies are subject to rot. The foliage is lush which mitigates the need for mulch.

Dormants I have tried to grow. Most of them came from my friend's garden where they were doing well.

BICOLOR BEAUTIFUL lasted 18 months here. Never recovered from the move--foliage was sparse and short and it never bloomed nor did it grow.
TEXAS BIG RED lasted 24 months, bloomed once. Foliage became grass in the second year.

Other plants that didn't grow and that I passed along to my friend:

COSENZA (one DOR parent--Shores of Time which was a parent of the pod parent, too)
FLAMINGO PARADE (one SEV & one DOR parents) Sent her a tiny plant and it grew well for her. She likes it
MARY ETHEL ANDERSON no parents shown. Got it from my friend and tossed it 3 yr later when it had shrunk to a small size
SONG OF THE EMPIRE (one EV & one DOR parent) in the Lost/Tossed file. Started shrinking and she didn't want it.
SYMPHONY OF PRAISE an EV that looked like it would work. Had it 4 yr and it never gained a fan and had a 2 week bloom cycle. Friend didn't want it. Maybe just a failure to thrive

That's about the best I can do, Maurice!

Arlene - Since I have acquired 9 new dormants, I will be watching their progress. I have already seen the decline of one of them (Persian Pattern). I will be watching it closely to see if it survives. It seemed to all but disappear this Winter and is coming back very sparse. I am hoping it is just a rest period and will catch up to my other daylilies in foliage and multiply, but I won't be surprised if it doesn't. I acquired it this past Fall without the very high temps of summer in central Florida to try to survive in. This summer here may be the death of it. (But am hoping not.)

Thank you to all for contributing to this very helpful conversation about summer dormancy and plants that are listed as dormants.

@beckygardener

Might you have a photograph of Persian Pattern as it is now?

I would also be interested in knowing when it arrived in Florida and where it was grown before that.

Thank you, for any details you can provide.

Great minds think alike! I just went out and took pictures of two plants that have dormancy in them and a picture of an EV daylily I received in November 2015. I only purchase from FL growers and now I only purchase plants hybridized in FL. Doesn't always work the way I expect, either.


BARBIE'S FAVORITE (SEV) Frank Smith. Frank labeled almost all his plants as SEV so I can only assume that this plant has some dormant genes. Purchased November 2013 from Michelle up in the FL panhandle. The plant looked very good when I got it--2 large fans. Barbie is just starting to wake up. This plant sent up 4 scapes the first year--all were 2 way with 7-10 buds. In 2015 it's ffo was 4/22 with a 6" bloom. It had 5 scapes, tallest was 23" all had 2 way br with 2-7 buds. The official stats for Barbie show her to be 36" tall with 6" blooms.



MRS. WILLIAM KEMBLE DU PONT is also a Frank Smith Plant. Purchased it in March of 2013 from Abundant Daylilies in north FL. Nice big plant when I received it. In 2014 the plant had 3 scapes with 2 way br. and 2-5 bc. By the fall of 2014 I wrote in my notebook that the plant was tiny and might not survive the winter. In 2015 she had 4 scapes. Tallest was 21" and 2 way br with 5-7 buds. No rebloom. Officially Mrs. William should have been 34" tall with 7" blooms.



This last picture is of PUNCHY PURPLE. It's an EV Lambertson plant that came from Michelle in November 2015. Nice plant when it arrived, but much nicer now!



You can see why I fuss over SEV daylilies. Since it is a sliding scale, there is no way to judge if the plant is at the EV side of the scale or the DOR side. I lucked out this fall--everything I got is big, bold and beautiful!

Maurice - Here are two photos of Persian Pattern. I received the plant (6 fans) on July 30th, 2015. They came from Carleton, Michigan. I potted them up because my new raised bed was not completed. I planted them in the raised bed on Oct. 4, 2015.

Here is a photo of Persian Pattern taken on Oct. 27th, 2015, about 23 days after planting it in the raised bed.:



Here is a photo taken of it today:



As you can see, the new foliage is very small compared to all the other daylilies in the raised bed. All those plants were newly acquired by me this past Summer/Fall 2015. I have not seen it bloom yet, so I can only believe that it is indeed Persian Pattern. (I am sure it is.)

The other smaller plant that is slightly to the upper left is Duchess of D'Orleans. (It was 3 fans when I received it from the same grower at the same time.) All the other daylilies are much bigger now.

Here is a photo taken in October 2015 with names of all the daylilies in that bed (except one that was added this Winter):



Note: Calgary Stampede and Raspberry Beret disappeared and have not returned so far this Spring.

Thank you for the photographs of the dormants as they are now, @beckygardener and @florange

While I don't have any experiments, I have experience. Daylilies have been grown by my family in central Oklahoma zone 7a since they arrived here in 1889. Hundreds of cultivars have been grown for the past 75 years. One reason for growing daylilies is because they survive and reliably bloom every year. We have daylilies from all over the USA. and from hybridizers in all growing zones. Our summer temperatures are as hot as anywhere except the desert southwest. It is rare for us not to reach triple digits F each summer. Our average July high temperature is 96F. We do get 4 seasons and regular winter freezing temps.

We currently grow about 600 registered daylilies and well over half are dormant. I think the dormants are more reliable than the evergreens. I have Florida evergreen cultivars that are registered at 35+buds that will have between 2 and 10 buds in my garden. They will only bloom every other year and never increase. The hard dormants will bloom every year with normal bud counts and increase to nice clumps in two or 3 years.

I am generally speaking based on foliage habits but looking at our daylilies this year, the dormants were just tips above the ground two weeks ago. Our temps have been mild with highs in the 50's, 60's and some 70's. Nights are still in the 30's and 40's with some freezing temps each week.. The evergreens and semi-evergreens look about the same as they have all winter while the dormants have grown 6-8 inches tall in two weeks.

I have a species -Hemerocallis dumortieri that blooms mid April almost every year. Our last freeze average date is April 1st. It will go from dormant to bloom in a few weeks. No other daylily will typically start blooming until late May about a month and a half later.

Maybe I don't grow the cultivars that can't take high temps but I am not at all particular when purchasing plants. I don't even think of the foliage habit of D/SE/E. I just buy based on what I want in a bloom. I have purchased plants from Florida to Wisconsin and all growing zones between. The only thing I try to avoid is getting plants too late in the spring. But sometimes I just want to buy from Michigan or Wisconsin and they will ship late for my area. Last year I planted all my late spring order in the shade. Now some need moved to a more sunny location.

I have never moved daylilies in February before, but this year the past few weekends were so nice that I have been gardening like it is April. I moved 20-30 daylilies in February.

Terry

@Terry thank you, for the information about the dormants growing well in your conditions.
The following is information about heat stress and I want to emphasize that I would never expect daylily growers to do experiments so this is just to provide general information to help understand some of the ins and outs of heat stress.

Arisumi did a designed experiment testing how temperature affected daylily growth. There is no doubt that temperatures of 85F and 95F caused problems. The experiment was done under certain controlled conditions and not under normal growing conditions in a field or garden. When a plant is growing in normal garden conditions there are many other factors that will affect how a plant will react to high temperatures, other than the maximum daily temperature.

For example, how quickly a maximum temperature is reached will affect a plant's response. How long the maximum temperature is maintained will affect a plant's response. The relative humidity, the wind speed, the amount, time and depth of any daily shade, the amount of rainfall, the amount, time and method of any watering, the depth of any leaf debris (soil temperatures are significantly modified by dead leaves on the surface, for example), all will have effects on how the plant responds to the maximum temperature.

Although maximum temperatures are important in determining heat stress, the actual pattern of the temperatures is also very important. As an example, suppose 85F caused some stress, 75F caused no stress and 95F caused much stress. Twenty consecutive days of 85F would cause a certain amount of stress. Ten days of 95F followed by ten days of 75F might cause more stress than twenty days of 85F. However if there were 20 days of 12 hours of 75F at night and 12 hours of 95F in the day then there might well be no stress (the cooler night might allow recovery of some to all of the daily stress). Yet if those temperatures were reversed so that the 95F was at night and the 75F during the day there might be even more stress than for the ten days of 95F followed by ten days of 75F.

The symptoms of heat stress depend on the level of heat stress that the plant experiences. One symptom may be pollen infertility, another might be pod abortion, or pod infertility, etc. Other symptoms may be early leaf yellowing and summer dormancy. Summer dormancy may be a daylilies attempt to escape heat stress and/or drought.

One also has to keep in mind that daylilies are genetically different in all characteristics. When it comes to temperatures, daylilies will have different minimum temperatures at which they die (lower lethal limit). They will have different maximum temperatures at which they die (upper lethal limit). They will have different lower temperatures at which they start and stop growing. They will have different growth rates as temperatures change. They will have different optimum temperatures for growth and probably different optimum temperatures for pollen fertility, pod fertility, leaf death (senescence), etc.

There has been more than sixty years of daylily selection during which there were significant changes in the proportions of daylilies hybridized in the south versus the north. That may have had effects shifting temperature ranges one way or another.

Below is a photo of the plants Arisumi grew at the different temperatures. It is easy to see that 65F was near the optimum for growth.



Below is a graph showing an example of what one would expect if one tested the effect of temperature on a group of 100 different cultivars looking for what temperature killed half of the cultivars. That is marked as 50 and is called the LT50 - the lethal temperature that kills 50% of the population. Temperatures below the lethal limit but somewhere above the optimum temperature for growth cause visible heat stress.



Below is a graph showing two hypothetical daylily cultivars with different lower and upper limiting temperatures for growth and different optimum temperatures.

Maurice - Very good information!

Now my question .... do you know if more daylilies have been hybridized in the south over the years to create more heat tolerant cultivars?

Does regular (sometimes daily) watering help with heat stress, especially during summer? Or is it more about the actual daily temps?

I am also wondering if a shade cloth over raised beds might help reduce heat stress?

beckygardener said:Maurice - Very good information!

Thank you.

Now my question .... do you know if more daylilies have been hybridized in the south over the years to create more heat tolerant cultivars?

I suspect that has been the case, but I have never done an analysis. A proper analysis would compare, over time, the number of daylilies registered by hybridizers identified to location. However, there is a simple check. That is, hybridizers move north less than move south. Daylily World moved from Florida to Kentucky but at least three hybridizers moved from the north to Florida in the same period that I know of - Stamile, Trimmer & Reilly. Another simple check would be to look at the ratio of registered dormants to registered evergreen and semi-evergreen by year going back to the 1940s. That assumes that at least in the past, more dormants were registered in the north than in the south. There is reason to believe that as in the 1940s southern daylily growers emphasized that they were more interested in growing evergreens and encouraging evergreens to be hybridized so that they could have green in their gardens during the winter.

Does regular (sometimes daily) watering help with heat stress, especially during summer? Or is it more about the actual daily temps?

That would need to be checked very carefully if over-watering can cause problems. Basically high temperatures cause more evaporation of water from the soil and plants. Plants need water to grow and when it evaporates it will also act to cool them. Water is lost from sand more quickly than from some other soil types, etc. Plants that are not growing need less water than when they are growing and have leaves, etc. If your plants are doing well overall I would think carefully before changing your watering.

I am also wondering if a shade cloth over raised beds might help reduce heat stress?

Definitely, I would think that is why some hybridizers use shade cloth - to reduce the effect of heat stress on fertility.

Below is a graph of tetraploid registrations by decade from the 1960s to now. It shows the proportion of daylilies that were registered as dormants in each decade. There appears to have been a predominance of northern hybridizers until the 1980s followed by a swing to southern hybridizers from the 1990s and continued later. I don't think that one can use the proportion of evergreens because I think there may have been a trend away from registering daylilies as evergreen and registering them as semi-evergreen.

I truly believe that registering daylilies as SEV comes from two divergent directions. It maybe the hybridizers are too lazy to watch and tell the difference or it may be a marketing ploy. In Januay/February, even in FL, it's very, very easy to tell which plants are EV or dormant or on the dormant side of SEV. The advantage of labeling a daylily as SEV would appeal to a exponentially larger market than labeling it as an EV, the inference being that SEV plants can be grown in a wider portion of the U.S. Yes, I have become very cynical on this subject.

Arlene - I suspect your theory is probably correct.

@florange I do not expect to be able to change your mind but I must politely disagree completely with you about identifying "evergreen" from "dormant".

There is at least one major problem with the foliage registration categories of dormant/evergreen/semi-evergreen. They are biologically incorrect. Dormancy relates to growth versus non-growth and evergreen relates to how long a leaf lives (ie through winter). Asking someone to classify a daylily's foliage to dormant/evergreen/semi-evergreen is like asking someone to classify a pie's sweetness to hot/sweet/semi-sweet.

The correct foliage category is deciduous not "dormant". Being deciduous is unrelated to being dormant or requiring chilling or setting buds or being hardy.

When daylilies are registered as "dormant" they are biologically deciduous; they may also be biologically winter-dormant. When they are registered as "evergreen" or "semi-evergreen" they may be biologically winter-dormant or ever-growing. A simple comparison should help make this clear. A maple tree is deciduous; it loses all its leaves. It is dormant during winters in cold winter climates. A pine tree is evergreen; it keeps its leaves (needles) through winter. It is dormant during winters in cold winter climates. Neither grows during winter in cold winter climate locations. They are both dormant although one is deciduous and the other is evergreen. Daylilies can be dormant and deciduous or dormant and evergreen.

Dormancy

The current botanical definition of dormancy is "Dormancy is a temporary suspension of visible growth of any plant structure containing a meristem".
Dormancy applies basically to buds and within buds to the meristem (shoot apical meristem or meristem for short, known commonly as the growing point).

Dormancy is unrelated to the presence or absence of leaves ("going down"). The loss of leaves does not indicate when a daylily became dormant or even if it is actually dormant. It may be dormant, on the other hand it may not be dormant; it may be creating baby leaves but not sprouting them or not sprouting them above the soil surface. The only certain way to know when buds or meristems are dormant is by slicing through samples of them and examining them under a microscope over a period of time. One may be able to get some idea of whether a bud is dormant by watching to see if new baby leaves are produced continuously over time but one cannot be certain one is correct.

Botanically dormancy is divided into three types:
1) ecodormancy - where the bud or meristem is not growing because of some factor in the environment (the growing conditions). All daylilies can be ecodormant. As an example, when it is too cold the daylily does not grow. A plant may or may not have enough time to form a bud when it stops growing due to ecodormancy.
2) paradormancy - where the bud or meristem is not growing because of some factor in the plant but outside of the bud itself. Apical dominance of an axillary bud (nestled between a leaf and the stem) would be one example of paradormancy. Most gardeners know that pinching off the growing point/tip will often cause lateral/axillary buds to sprout and produce branches. This is an example of paradormancy.
3) endodormancy - where the bud or meristem is not growing due to factors within the bud or more precisely within the meristem. This is the type of dormancy that we think of as being present in the autumn that prevents tree buds from sprouting and that can only be removed when the bud experiences enough cold (chilling hours or units).

Only endodormant buds or meristems require chilling to sprout or grow again.

All daylilies can be dormant - whether they are deciduous (incorrectly registered as 'dormant'), evergreen or semi-evergreen. The evidence for this is present in every garden with daylilies that has all three registered categories and that is far north enough. I am in zone 4. I do not check foliage type when I order daylilies from the southern US or California. I grow between 600-800 registered daylilies. Since I don't check registered foliage type I do not know what percentages of each type I grow but it is probably more evergreen and semi-evergreen than registered 'dormant' (I do not have a listing of the daylilies I grow). They all are dormant during winter. Nearly all form buds. I estimate that less than a dozen appear to be caught by winter (extreme low temperature) too quickly to form a bud.

I am going to describe an imaginary situation. Supposing instead of buying all the registered daylilies that I grow, I had hybridized them all here. I would have registered them all as dormant (because they set buds and stop growing). Now say I took one hundred of those daylilies and divided their clumps so that I had 10 sets of one hundred. Then say I gave one set of 100 to each of 10 gardeners from New York to Florida and asked them to classify each of the daylilies as to the registered foliage types dormant/evergreen/semi-evergreen. This is what I would expect to find. In the North the gardeners would classify more of the daylilies as dormant and fewer as evergreen. The further south the gardener, the more evergreens and the fewer dormants.

Going into winter, daylilies could be endodormant or ecodormant (we will ignore paradormancy). In both cases they are not growing. In both cases they may have set buds or not set buds. If they are ecodormant they have presumably become ecodormant when they experienced the low temperatures that make them ecodormant. Those low temperatures would differ for each cultivar. When or if that low temperature is reached for a particular cultivar would depend on the location that it is grown in. If they are endodormant then they may have become endodormant when they experienced the day-length/night-length that makes them endodormant or the low temperature that makes them endodormant or they become endodormant completely autonomously or they require some combination of factors. If they are endodormant then only if photoperiod or an autonomous method sets the endormancy would they become endodormant at the same time in different locations.

No daylily is currently known to be endodormant in the autumn. Daylilies are known to be ecodormant in the autumn and to have set buds.

It is relatively easy to check the type of dormancy being shown by a plant. Stout did this for a number of his plants in November in New York - they were all ecodormant. I have checked it for those daylilies that have been identified to me as "hard" dormants. I have checked some of those daylilies in December, November and October. They were all ecodormant. I have checked some daylilies that I received in September but that I do not know whether they were dug in August or September. They were all ecodormant. I continue to look for and test daylilies that might be endodormant.

Plant species that are endodormant in autumn typically go through three phases. They are paradormant, then they become endodormant and finally they become ecodormant. They typically have buds in late summer. Those buds do not sprout before winter because they are endodormant. They sprout the next spring when they are ecodormant. Endodormancy prevents the buds from sprouting at the wrong time of the year - the autumn.

Daylilies do not do this. They tend to sprout in the autumn. Different cultivars tend to sprout at different times and grow at different rates in the autumn. Some daylilies seem to not sprout - or at least their buds may or may not appear above the soil surface. However, that may depend on where they are grown and how they are grown. It almost certainly will depend on temperatures and may also depend on day-lengths. Unfortunately, there may be no real difference between a cultivar whose bud does not appear above the soil surface (or which takes a long time to appear above the soil surface) and one whose bud does appear above the soil surface. The only difference may be that one may grow faster and at lower temperatures than the other. One would need to measure the height that buds sprouted both above and below the soil surface (or in total - disregarding any effect of the soil surface making it difficult to see how much a bud had actually sprouted). The figure below shows what one should see if there is a potential difference between those cultivars that have not sprouted above the soil surface on any given date versus those that have.



In the figure there are cultivars that have not shown any bud growth during some period of time (they appear to be dormant - not growing). If they simply are one end of the tail of the amount grown then the number of such cultivars will be as expected for the shape of the distribution. However, if they are in some way different from the other cultivars then as a group they will not be present in the numbers expected (based on the growth of all the other cultivars). If one did such an analysis on daylily bud growth in the autumn one then could also test those cultivars to see if in fact they did not grow when given good growing conditions at that time (autumn) and see if they were endodormant.

You seem to forget that I only purchase daylilies that are grown and hybridized in FL. In THIS climate, there are distinct difference in foliage growth in winter months between evergreens and dormants. I don't know what happens in Canada but have strong suspicion that your brutal climate would send any daylily underground during the winter--or at least as far underground as they can go. Down here, the winters are mild. Although we can get cold, it doesn't last very long. It is not difficult at all in January to look at a garden and to point out which plants have dormant traits and which have evergreen traits. In my experience, the evergreens continue to stand tall, put on fans and generally look very good. Daylilies with dormancy in them will shrink down to 3-4" high and stay that way until late in March. They may add fans, but they will not bloom as early as evergreens because they have to come out of their funk, grow and then bloom.

I may be classifying my seedlings all wrong when I look at Maurice's explanation. But, I am not a scientist, far from it, so when I register a daylily as dormant, semi-evergreen or evergreen, I base it on my observations of the plant during the winter months. If it totally disappears, it gets classified as dormant. If it has a bit of green it is semi-ev, and if it has more green than normal, it is evergreen. Honestly, and I don't mean to be condescending to anyone, when I first got into daylilies 20 plus years ago, this was the way most people did classify them at that time. Whether the top hybridizers have changed their way of doing it, I really don't know as I am a very small scale grower compared to most.

Excellent, Cindy! The people who purchase you plants will be thrilled. One of the reasons I don't buy from "up north" is that something that is evergreen for you may not be evergreen down in in the near tropics. I'm not lumping everyone together, but since daylilies grow from south FL to MI, our environments are so diverse! Where I am, EV's are the only thing that thrive. Period. I'm always happy to see people who try their best to do right. That means their customers will be happy!

Arlene, just out of curiosity, when you say they shrink down to 3-4" until March do you mean the old leaves die completely and all you can see is resting buds poking up 3-4", or do you mean the foliage dies back but not completely to the ground, leaving some green at the base as would be seen in a semi-evergreen?

Thanks for your vote of confidence Arlene!!!