beckygardener said:..... much of the "older" foliage is turning yellow, then shriveling up and changing to brown. The older leaves are dying as the new ones grow in. Is this because they are coming out of Winter dormancy (including evergreens and semi-evergreens) and putting out new foliage?

Becky, there are several different patterns to how leaves age and die.

The yellowing and aging of leaves is called senescence. It is separate from dormancy.

When a fan sprouts (comes out of dormancy) a new leaf is produced every few days. We could think of the new leaves as being born one after the other. How many days there are in between each new leaf appearing and how quickly the leaves grow to be adult size or mature depends strongly on the temperature but also on other factors. Leaves have certain lifespans - they can stay alive for a certain number of days. How many days they stay alive will probably be different for different cultivars but is also strongly affected by temperature.

The leaves on your plants might be yellowing and dying because they have reached the end of their normal lives. This sort of aging can happen throughout the growing season. Each leaf would start to yellow and die when it has reached the end of its normal lifespan. The deaths of the leaves would be separated by approximately the same number of days that separated their "births".

Another pattern of aging is called top senescence. That is when all the leaves start to yellow and die at the same time. In many plant species this happens after the plant has flowered. This can also happen when the plant begins to go dormant. Or the plant can go dormant but the top (all the leaves above the ground) may not senesce until much later.

The leaves of a plant can also die at the same time when the plant has experienced a strong stress. Very low temperatures or very high temperatures, strong drought perhaps with the leaves wilting, too much fertilizer and so on may cause all the leaves to yellow and die.

Can daylily plants go dormant when they are not receiving enough fertilizer?

Yes, how much fertilizer the plants receive can change how daylilies grow. How much water they receive can also probably change how they grow.

The best example I can give is 'Heavenly Harmony". It normally grows in my field without any added water or fertilizer (quasi-natural conditions). Growing in those conditions a scape appears in early June and it does not produce any new leaves after that until September. Its crop of leaves stays green until late August or early September. It is dormant from June to September. One autumn I fertilized it heavily with high nitrogen. The next spring as it started to grow I again fertilized it heavily with high nitrogen. That year its growth pattern changed. It produced new leaves all summer. 'Ophir' responds to high nitrogen fertilizer in much the same way. Its normal growth pattern when not fertilized or watered is to become dormant in July and stay dormant until the next year. Again its leaves stay green and they do not senesce until October or November. When it is heavily fertilized with high nitrogen it grows new leaves all summer and has even rebloomed.

Maurice - I am glad you confirmed what I had also seen in my own garden. I have not seen water change growth (unless severe drought conditions), so that is why I did not include water in the equation. Mine are all hybrid seedlings and with several doses of fertilizer throughout the year, they often put on growth for a much longer time than without the additional rounds of fertilizer.

Hmmm, I have Heavenly Harmony and have never really looked at it closely to see how it grows.

I realize this is an older thread, but I have a question on dormancy and growing daylilies indoors... everywhere I have read, folks advise against growing daylilies indoors, period (and with quite the conviction). I have seen comments that dormants, and many SE and EV varieties require cold periods for general health as well as to bloom. Recently, I asked about advice concerning some young seedlings I have in pots that I fear will not make it thru a harsh winter here in NW Michigan (zone 5 with zone 4 temps from time to time).. my inclination was so bring them indoors and then plant outdoors in spring... not a single person in the group who responded felt that was a viable option, because of dormancy considerations.

My question is this, are there dormancy (or other) considerations that would prohibit me from growing seedlings or adult daylilies indoors until they bloom, if I am inclined to do so? From my point of view, and my limited experience I do not see why I cannot grow daylilies in pots indoors for an extended period as long as I provide suitable lighting, container size, growing media, nutrients, etc.. Am I missing something...

Any thoughts appreciated,

Jeff

Jeff,
I am not familiar with growing daylilies up north, but I was thinking a green house would be the perfect thing to grow seedlings in during frigid weather.
I know daylilies are grown in green houses, so I am not sure what the exact issue is.
I will look forward to others who are familiar with northern daylilies to respond.

@admmad
Can you help with this question about dormancy and growing daylilies in Greenhouses?

@goedric @seedfork

There is no problem related to dormancy with growing daylilies inside during the winter, I have been doing so for many years without problems.

There is no objective evidence that any daylily needs to experience a period of near freezing cold for good growth and there is objective evidence that all or nearly all daylilies do not require any near freezing cold for flowering.

If you leave your daylilies outside so that they experience winter cold then some of them may go dormant. When you bring them inside and give them good growing conditions many of the dormant daylilies will start into growth quickly with no problems. It is possible that a few of the dormant daylilies may stall (start growing and then stop). To get those to grow may require patience but I have found that giving any that stall warmer temperatures and high light (closer to outside light intensities and temperatures on warm spring days) gets them started into growth in less than a week.

It is simpler, in many cases, to simply bring the daylilies inside before they show signs of slowing growth (before they lose their new leaves). I am in zone 4 and if I bring daylilies inside by Oct 15 they grow without problems. Stout was in New York city and he found that daylilies brought inside into a greenhouse without extra lighting about the middle of November grew well.

All daylilies may experience a period of dormancy, whether they are growing outside or inside. That may partially depend on how well they are grown and the temperatures and watering that they receive. It will be affected by how well they are fertilized. Dormancy is a period of time when a plant stops growing. That can be seen by checking whether a daylily is producing new baby leaves in the centre of the fan on its normal schedule (which depends on temperature, light, nitrogen fertilizer, etc.). It is dormant when it stops producing new leaves. It can be dormant yet have a full fan of green leaves. That is a normal response. It will start into growth again when its crop of leaves ages, yellows and dies. That is also normal, leaves have a limited length of life and then they need to be replaced. That is called discontinuous growth. If it is given optimum growing conditions it may simply grow continuously meaning it will continuously produce new baby leaves and slowly but continuously some of the older leaves will yellow and die.

How a daylily may react specifically will depend on your location, the weather the daylilies experience outside, the conditions they experience inside, when they are brought inside and what is done to them when they are brought inside (for example, removing all their leaves when brought inside or leaving them), etc.

Maurice, one for you. GLORIOUS AUTUMN registered as a dormant, didn't come back this year. Planted in 2013. It always struggled here in the subtropics and was always going backwards.

@gleni
Part of the problem is that whether a plant is registered as a "dormant" does not provide any information about whether the plant is able to grow well at high temperatures and locations with high temperatures during the growing season tend to not have low temperatures during their "winters". Of the two possible problems the winters cannot simply be assumed to be the problem.
Plant growth and development depends on a number of factors but an important one is temperature. All plants have three important temperatures for their growth and development. These are called their cardinal temperatures. There is a base temperature below which no growth occurs. For some daylilies that may be about 2 C for others it may be between 6 C and 8 C. Then there is their optimum temperature. Arisumi indicated that was near to 72 F (about 22 C) for the cultivar he examined. Lastly there is a maximum temperature above which there is no growth. Temperatures above the maximum are likely to be detrimental to the health of the plant.
Many ornamental plants have maximum temperatures about 31 C or close to 88 F.
If a daylily registered as "dormant" was hybridized in a location that did not experience high temperatures regularly and from parents that were also hybridized in locations that did not experience high temperatures regularly then it is unlikely to do well in a location that regularly has high temperatures. Such daylilies may well be registered as "dormant" but it is not whether they are dormant or not that may affect their growth, flowering and survival in locations that do not have cold winters. It may be that those same locations have high temperatures throughout the growing season that detrimentally affect the growth and flowering of the plant.

Note the daylily Arisumi examined flowered very poorly at 85 F and not at all at 95 F. It grew poorly at both temperatures.

Specifically 'Glorious Autumn' was hybridized by Kirchhoff in Florida and even though registered as a "dormant" should grow well in Florida type temperatures and weather. Its parent 'Carrot Rouge Truffle' is also likely to be have been hybridized in Florida (registered by Schwarz-Kirchhoff) and although registered as a "dormant" should also grow well in Florida type temperatures and weather. I would look for something other than the "dormant" designation for why it may not have grown well for you, since it presumably grew well for Daylily World in Florida, well enough to be introduced.

@gleni
It might be interesting and possibly quite informative if you had a record of how 'Glorious Autumn' grew during each year (how it increased, how it flowered, how many leaves it grew, what size leaves, etc.) along with a record of your daily weather.

Warm winter locations also have another possible cause for possible daylily problems and that is the warm temperatures may allow more generations of insect pests to be produced and for populations of insect pests to increase more than in those locations with winters cold enough to reduce pest populations. Similar effects might also apply to disease pressure.

Maurice in addition to you Gerry aka @Profesora also grows and blooms daylilies indoors. It would be interesting to hear how Gerry does it also.

I've often grown daylilies indoors during the winter, usually new ones received too late in the season to plant in this climate, or to watch for spring sickness. They go on a sunny windowsill facing south-east with no supplemental lighting and some do flower if they are of flowering size. Winters here are very cold and the room can be cool especially close to the window. If they are brought in after the leaves have died back most sprout and start to grow within a week or so of coming indoors (whatever their registered "foliage habit").

Maurice, thank you for your expertise!!
Does the amount of light available control blooming cycles, given a consistent temperature?
If the optimum temperature is 72F, would a plant just continue to cycle through scape, bloom, new fan production indefinitely? Or would the length of the day factor into this in any way?
Many Thanks!

I have made three attempts to grow 'Smoky Mountain Autumn' and it just does not seem to be able to take the hot summers here. It just diminishes each year. I do still have some scattered fans of it, but I doubt they will be there by the end of next year. I don't recall reading before about Cardinal temperatures, but to me that seems to explain the problem I have with 'Smoky Mountain Autumn'.

SueVT said:Maurice, thank you for your expertise!!

You are very welcome.

Does the amount of light available control blooming cycles, given a consistent temperature?

Yes, as long as the amount of light means its intensity. When other factors that affect growth and flowering are provided optimally then the single factor that is not will be the controlling factor - the amount of light provided affects the amount of growth a plant can produce.

If the optimum temperature is 72F, would a plant just continue to cycle through scape, bloom, new fan production indefinitely?

As long as the other factors necessary for good growth and flowering, e. g. fertilizer, water, etc. are provided then generally yes. We do not know for certain whether there are any daylily cultivars that are discontinuous growers when provided with optimum growing conditions. We also do not know if setting pods and the number of seeds developing would have any effect on growth and flowering. It is quite possible that they would. If that is the case then the daylily would continue to cycle as long as no pods were allowed to set.

Or would the length of the day factor into this in any way?

The research that has been done (but not published) on daylily flowering indicates that the length of the day (better looked at as the length of the night) does not have an effect (assuming that the length of the day is separated from the actual amount of light delivered (intensity).

thank you Maurice.

Pehaps this explains why some of my seedlings, which were started indoors last November-December, are now blooming as if it were June. They have attained a certain size and are ready to bloom.

Others (most of my 500 seedlings) are not going to bloom this year, perhaps because of genetic characteristics leading to later season bloom. If I were to (theoretically) move them all indoors, these would proceed to bloom in a couple of months, as they reached a certain point of maturity. Is this right?
A need for dormancy is not the issue.

@SeedFork

I have made three attempts to grow 'Smoky Mountain Autumn' and it just does not seem to be able to take the hot summers here. It just diminishes each year. I do still have some scattered fans of it, but I doubt they will be there by the end of next year. I don't recall reading before about Cardinal temperatures, but to me that seems to explain the problem I have with 'Smoky Mountain Autumn'.

'Smoky Mountain Autumn' (SMA) was hybridized by Guidry in Abbeville, Louisiana, apparently USDA zone 9a. You have Enterprise, Al. indicated as Zone 8b. Would your summers have higher temperatures than Abbeville or would they have high temperatures for longer continuous periods than Abbeville?

You wrote, "It just diminishes each year". If you receive it when purchased as two or say three fans then it should not be able to last more than a couple of years. Is it in fact managing to grow and increase in some years and declining in others?

Is it possible that up to 1988 when SMA was registered the weather was cooler in Abbeville? It has been 27 years. It is possible that there are nearby climate records that cover that period.

The first time was a just a couple of fans, then twice I received clumps that I planted in different locations (varying amounts of shade) of four or five fans each.
Looks like the temps on a monthly average and yearly average are pretty much the same with the two locations. It appears the overall temp. of Alabama state wide has not risen in the past 50 years, and the same for La. So, back to the drawing board.

SueVT said:thank you Maurice.

You're welcome.

Pehaps this explains why some of my seedlings, which were started indoors last November-December, are now blooming as if it were June. They have attained a certain size and are ready to bloom.

Yes, once a daylily has reached blooming size, it will bloom.

Others (most of my 500 seedlings) are not going to bloom this year, perhaps because of genetic characteristics leading to later season bloom. If I were to (theoretically) move them all indoors, these would proceed to bloom in a couple of months, as they reached a certain point of maturity. Is this right?
A need for dormancy is not the issue.

They would bloom when they reached their required size/maturity, that may take substantially longer than a couple of months depending on the conditions inside. There is no need for a period of dormancy to flower. There is also no need for the daylilies to experience a period of cold to flower. That was shown scientifically by research. That research used a handful of cultivars, one of which was 'Stella de Oro'. None of them required a period of cold to flower, not even 'Stella'.
It was also shown by Doorakian who grew daylilies from seed to flowering in a greenhouse in Massachusetts from August to May kept between 72 and 80 F with no artificial lighting.
It is important to keep in mind that although the length of the day/night has no effect on flowering it may have an effect on the length of life of leaves. We do not know for daylilies.
When you move them indoors is also an important factor, as is their growing condition when you do so.
Right now many of my daylilies in my field are losing or have lost their leaves. Some have not. Some of the ones that have lost their leaves have sprouted new young green leaves. Others show buds just sprouting and yet others probably have buds under the soil surface. There may be others that have new young fans of vibrant green leaves.
In your location some of your plants may have grown full fans of new leaves and stopped producing new leaves. If so, they may not produce any new growth after being brought inside until their new fans age and die. Those leaves are producing resources that the crown and/or roots are storing for future use.