Friday, May 27, 2016

Daylily Companion Plant White Clover

Daylily Companion Plant
White Clover 
Trifolium repens

This section has had the clover pulled from around the plants and then spread around the plants as mulch, but the clover has been left growing through the path to reduce mud and create soft pathways.

White Clover
Trifolium repens


A Green Mulch while growing, helping to retain topsoil and soil moisture.

 A Nitrogen fixing Legume that adds nitrogen to the soil while growing. 

Releases nitrogen and other organic nutrients when cut and used as a mulch.

Depending on the type of White clover used, plants may mature at 12" down to 6" with Dwarf types of White clover.

Dwarf types may be preferred in display beds or visible/ornamental gardens, however, they also produce less organic matter through the lower volume of leaf and stem produced.

A perennial that survives cutting and produces abundant growth.

Abundant growth results in large amounts of organic material (cut clover leaves and stems) to use as mulch.

Abundant growth also fixes nitrogen into the soil while holding topsoil in place.

As Hemerocallis are monocots, they tend to like nitrogen and respond well to the presence of nitrogen in their soil.

A nitrogen fixing legume that doesn't outgrow the daylilies through outcompeting them is a valuable companion plant to the daylily indeed.


Before


After

The areas of the gardens where I am using green mulch from growing clover, which I periodically cut and use as organic matter mulch, are my hybridizing gardens. I started cutting clover yesterday, working in small sections and cutting or pulling the clover leaves. I have generated a huge amount of mulch for free this way that produced nitrogen while it was growing and will now release nitrogen and other organic nutrients as it decomposes.

I have been interested in permaculture for many years, so creating this natural nitrogen-additive, soil improvement program that reduces erosion, soil drying and weeds while retaining moisture is just so exciting to me. It is also very low input and very high output at the same time. The areas of the main hybridizing garden where I have been doing this for the last few years have gone from orange/peach sand and clay blend with minimal topsoil to rich, heavy brown to black soil with lots of earthworms. 


Before


After


By being forced to allow the clover to grow longer due to circumstance (rain and a stiff knee), I have been able to see the interaction, competition and cooperation of the clover with the daylilies. The daylilies have flourished as has the clover, and the Daylilies with the most clover around them seem to look the best. This is regular white clover (Trifolium repens) growing to about 12" tall at maturity. I took some pictures today as I was working, of before and after shots of the garden, with 'before' uncut white clover and 'after' of the cut clover spread around the plants as mulch.

The roots and main vining stems of the clover are still in place, so they will continue to produce nitrogen as the leaves regrow. I also have produced a large amount of mulch for free that is nutritious to the daylilies. This ground-cover/mulch combination is great for me because it continues to generate mulch but even when it isn't cut for long periods of time, daylilies grow well in it as the clover does not out-compete the daylilies while the added nitrogen of the clover seems to in turn help the daylilies to grow profusely.

I still have to weed, but mainly for larger weeds and trees, like maple, poplar or poke, but not for the hundreds of annual and small weeds I used to deal with in that garden. It is important to understand that a garden is not a natural thing. All gardens require some maintenance. It is my experience that there really is no such thing as a weed-free garden. It is all in how you manage weeds, especially removing large and difficult-to-remove weeds in a timely fashion. No garden of any form can go without ever being weeded, because transitional weeds and trees will begin to grow and return your "garden" to pristine "unkempt-disturbed-field" environment, which will eventually lead back to forest.

What I find important about the clover is that when it has made a full ground cover in a particular area, it suppresses the germination of many seeds and drastically reduces the number of species, but it takes time to get the clover to this point. You have to allow it to grow and encourage it to cover areas that are bare. Uncovered soil is an invitation to weed seed germination. Clover makes thick mats of runners, leaf stems, bloom stems, blooms and leaves. In turn it shades the ground well and much germination is suppressed. That then creates conditions where you are not continuously battling weed seedlings, though you will have to weed some and preferably in a timely fashion, if at all possible. 

I wish clover would work in the seedling beds, but I don't see any way it can. I will continue to trial it and may experiment with some dwarf forms, but I don't think the seeds could germinate through it, though older seedlings of several months or more do fine with clover growing around them. My smallest seedling bed is in the hybridizing garden and those seedlings have not been smothered out and have grown in a good manner. I think I am going to be moving over to this method with all my beds except seedling beds. 

I am now looking into a dwarf Dutch white clover that only gets 6" tall. It may be even better than the normal sized type I have, but it may not produce as much dry mulch. However, it might look tidier in gardens where people want a shorter ground cover, even if the daylilies do fine in the 12", taller version, but I know the 12" forms work well and has added considerable benefit to my poor soil just by growing in it. Did I mention it was free and most people weed it out of their gardens? :-) Seed is also inexpensive for 5 lbs online. That should more than cover all my small fields.

Please don't imagine I am saying you should use White clover as a green mulch and ground cover. I am simply saying that I am glad I have used it and will continue to do so, because I have found it to be beneficial on many levels. However, if using White clover as a green mulch and ground cover interests you, I certainly encourage you to make a web-search for more information. There is much out there to be found. I will continue to update this page periodically.

The cut clover leaves and flowers, and leaf and flower stems, will now brown and die becoming a dry mulch. The worms will gradually pull the dried, decaying leaves and stems into the soil to release their nutrients. The clover also gradually regrows and fills back in, so you get the benefit of multiple cuttings through the year, though it should not be cut as often as lawn grass. I am finding about once every two to four weeks is probably enough and will still provide ample mulch to completely cover the soil surface, even in the areas where the clover hasn't fully established yet. As well, where there are mature seed heads in the cut matter, there is a good chance of spreading the clover seeds into bare areas, further helping to make a complete covering for the garden soil.


Before


After

Monday, May 16, 2016

Daylilies in Asia

What is a Daylily?


Part 3
Daylilies in Asia

Once mankind began engaging in agriculture and became settled, our adventure with changing wild species of plants and animals through the process of domestication was set in motion. While hunter-gatherer peoples certainly could impact natural environments and the species of plants and animals within those environments, there is no evidence of any active domestication by hunter-gatherers. This process apparently only fully arose later as humans became sedentary, living in settled communities.

The beginnings of agriculture is generally attributed to the time after the Younger Dryas at around 10,000 b.c.e. or later. The first domesticate is considered to be the dog for animals and wheat for plants. While dog domestication appears to have begun much earlier when humans were still hunter-gatherers through a unique set of circumstances, the domestication of wheat is thought to have occurred in modern-day Turkey after the Younger Dryas. 

Rice was the first major plant domesticate in Asia, generally attributed to 8,000 - 7,000 b.c.e. However, some evidence suggests that rice was domesticated earlier, perhaps are early as 16,000 to 12,000 y.a., though this may represent wild-collection of rice by hunter-gatherers, or perhaps a transitional phase (protoculture) from collection of wild populations of grains to full domestication. What is clear though is that the main body of the work toward domestic strains of rice occurred between 7,000 and 4,000 b.c.e.

It is clear though that rice was not the only domesticated crop raised in early Asia, and plants have been domesticated in Asia up into modern times. Domestics deriving from Asia include Foxtail Millet (which may go as far back as rice in Asia as a domesticate), Bottle Gourd (also as far back as rice), Water Chestnut, Perilla, Burdock, Broomcorn Millet, Garlic, Hemp, Soybean, Peony, Chrysanthemum, Azuki Bean, Chenopodium, Eggplant and Edamame, just to name a few.

Many other plants are utilized in Traditional Chinese Medicine and the historic herbal medicine that proceeded it, but were not domesticated, historically having been gathered directly from the wild. Many of these plants are now grown commercially to meet the demand for them as wild populations dwindle while others are still collected. In between those plants that were fully domesticated and those that were gathered directly from the wild were plants that were grown in captivity, but were not actively selected in the way the true domesticated plants were to change them to meet the needs of the growers. This is generally considered 'vegiculture'. The Hemerocallis seems to fall into this middle group historically in Asia. That is, they were grown in gardens, but they were not significantly changed from the wild types.

Domestication of plants has generally fallen into two main categories - annual crops that are generated through sexual reproductions (seed generated) and those that are perennial crops and are generated through vegetive reproduction such as division, grafting, rooting, etc (vegiculture). With annual crops, there is a complete turn-over of the genome every year with the potential for genetic change that sexual reproduction on such a scale implies, allowing for selection to be applied over time and causing radical changes from the wild predecessors. 

Perennial crops are not always produced through sexual reproduction, and perennials that are easily reproduced through vegiculture may rarely be grown from seeds. This makes the changes one may find in annual crops rarer in perennial crops historically (except for certain examples such as Peony or Chrysanthemum that have been actively bred for their flowers in addition to other uses), and thus little selection may actually be applied to these perennial species. For this reason, such crops may remain very close to the original wild forms for long periods of time even though they have been grown as a domestic crop into antiquity. So it seems to be with the Hemerocallis.

We know from ancient records that Hemerocallis have been grown in gardens and used as food and medicine in China for at least 2,500 - 3,000 years. It seems likely to me that their use goes much further back in time. I would suspect they were a menu-item for the hunter-gatherers in pre-agricultural Asia and as humans became settled, beginning to practice agriculture, they brought wild Hemerocallis species into their settlements both for utility and beauty.

While I cannot say why the Hemerocallis was not treated as Peony or Chrysanthemum in terms of selection for flower type, I might make the following suggestions on why so little modification was made from the wild species in terms of the uses of Hemerocallis as food and medicinal crops.


First, the Hemerocallis seems quite suitable for the needs it was used for. Unlike the shattering seed heads of wild wheat, the wild Hemerocallis species have no traits that make them difficult to gather. As the young shoots, flower buds and spent flowers are the main sources of food from the species, there was simply nothing to modify there. The species were suitable as-is in these regards.

Being easily increased through vegetative reproduction and especially with the running habit of the fulva forms, it seems likely that little sexual reproduction would have been actively pursued, with seeds (and new seedlings) being more of a random occurrence than a regular phenomena. When we add the self-sterility of some species forms and the difficult fertility of the triploids, these factors may have helped to make sexual reproduction of Hemerocallis a rare event in captivity. That doesn't mean it didn't happen on occasion, either by chance or intention, but the lack of forms drastically different than the wild species seems to point toward sexual reproduction being rare over the course of the centuries that this genus has been kept in captivity.

To add to the above, with self-sterility, in situations where entire communities were growing vegetative clones of one form, the chance of sexual reproduction becomes even more slight. While some individual gardeners/farmers may have known to cross forms to get seeds (or were growing multiple forms and simply got seeds through pollinator action), and there may have been individuals actively engaged in this activity, it was clearly not the common event as in Peony or Chrysanthemum, or annual crops such as rice, millet or wheat. 

When we look at the changes made to the genus Hemerocallis in a mere century in the West, we can see there is considerable genetic diversity within the genus. The lack of that phenotypic expression in pre-western garden forms in Asia, I feel, is another datum pointing to little active breeding in Asia throughout the centuries. Clearly, much change was made to Peony (especially the tree peony) and Chrysanthemum from their wild progenitors over the centuries in Asia, so we know the process of breeding and selection was being utilized historically in eastern Asia. I can only surmise that there were reasons the same was not applied to the Hemerocallis.

It certainly isn't  that they were unpopular. They were a common garden flower and food/medicinal crop for many centuries, with much lore and myth attached to them, as well as there being a good knowledge of the uses of the plant. So I can only suspect that a combination of factors kept the Hemerocallis very close to the species-types throughout centuries in Asia. As I have suggested above, I suspect the growth habit and fertility issues are at the basis of this lack of change within the genus in captive situations.

However, none of this is to say that no changes occurred. 

Areas where I think some change is implied occurs within the two main branches of the genus - the oranges and the yellows. 

In the fulva group, the "oranges", there are many forms known in Asia. While any of these could be wild-occurring regional variations, chance mutations or interspecies intergrades, some of them may well represent forms derived from garden-produced seedlings. Certainly, the diploid forms of fulva are fertile, and even when self-sterile, they can cross with other forms of fulva and other species of Hemerocallis, as we have seen from the work of Stout and others within the last hundred years. This would open the door for, at the very least, chance seedlings if not actual intentional production of new forms. 


Areas where domestic selection may have occurred is the doubled tepals of 'Kwanso' and 'Flore pleno', the variegated foliage of some 'Kwanso', the more pink or red flowers of forms such as 'rosea' formas and 'Chengtu', etc. While any of these traits could have arisen in wild populations and simply been collected and brought into captivity, these are also the types of ornamental traits one might expect to find favored and valued in captive-produced seedlings. Further, even where these traits may have come from wild-collected specimens, any garden where wild-collected specimens were brought together to grow would have been fertile ground for seedlings to emerge carry variations of these traits, and thus allow for captive selection to be applied. 

None of these traits would have inhibited the use of such specimens in their traditional food/medicinal roles, and in fact, all the above forms mentioned are grown in Asia for these traditional purposes, as are the other fulva clones. My experimentation with the forms of fulva I grow show that each form has a slightly unique flavor - an important point in a food plant and a culture with a highly developed cuisine tradition. Some clones are grown exclusively in some areas, while in others multiple clones are utilized. 

Another point to consider is bloom-time. By growing clones that are early (Europa), mid-season (rosea), late (Hankow) and very late (sempervirens), a much greater supply of food would be available throughout a much greater portion of the year. The same effect could also be achieved by growing both yellow and orange types that flower at different times throughout the season.

The triploid forms of fulva imply that the diploid versions on rare occasions produce unreduced gametes. Thus the triploid forms could have arisen in the wild through chance or in captivity through chance. However, the presence of the triploids, with their low-fertility, robust size and rambunctious rhizomatous growth habit may have made the chances of new seedlings that much slimmer, as the triploids are cultivated extensively in Asia and would have been a natural choice for their superior production of larger shoots, buds and flowers.

In the yellow category, many species are attributed, but how many of these are really species or wild-occurring species hybrids and how many are captive hybrids and forms? That is a difficult question to answer. First, it is very difficult to determine what the actual species are. Second, while some species forms show self-sterility, not all do, and some of those that do show self-sterility are sterile with their own clone, but not with other individual clones of the same species.


When we look at the yellow types grown in captivity in Asia, there are forms (just as we see in the fulva complex) that have not been shown to occur in the wild. For instance, while wild H. citrina is known, there are many clones of citrina in captivity. Likely some of the yellows in culture are clones, intergrades or hybrids of the true, wild-type yellow species.

Within the yellows, there are certain traits that may have been enhanced in captivity. Two that spring to mind are branching/bud count (important traits for the production of flowers as food) and the length of tepals in certain types such as some H. citrina forms (i.e., 'Baroni', etc), which would also give more food per bud. Such selection would fit with the uses of the plant and it is important to remember that in China there are only considered to be two basic types of yellow daylilies - tall yellow and short yellow.


H. citrina clone showing very long buds/tepals

A final point to consider is that there may have been many garden forms of Hemerocallis that have been lost throughout the centuries. Eastern Asia, especially on the continent, has seen many wars and much upheaval and destruction during its long history right up into modern times, and there is simply no way to know what wondrous forms of the many domestic plants and animals may have been lost over the centuries.

While it is impossible to make any definitive statements on the specific origins of any particular type, we can say that the many forms of Hemerocallis that were found in captivity and in the wild during the nineteenth and twentieth centuries in Asia provided the materials that Western horticulturalists would use to produce the amazing array of daylily cultivars that we know in the West today.

Next we will look at the early hybridization of the Hemerocallis that set the ball rolling in the West toward the amazing array of garden daylilies that we now know.



Sunday, May 8, 2016

The Species

What is a Daylily?
Part 2
The Species of the genus Hemerocallis 

The phylogenetic relationships of the Hemerocallis species is an interesting if sometimes confusing subject.  This old genus of Asparagales monocots has been in proximity to humans for some tens of thousands of years, modern man having been in Asia since at least 50.000 y. a., and Hemerocallis appearing to have been there for more than 25 million years. 

Hemerocallis has been an agricultural crop in much of Asia for a couple of millennia, if not longer. For me, this long term potential for intermingling of captive-selected, feral and true, wild-species materials leads to potential admixing and selection for type that might not happen in fully wild conditions with no human intervention. 

Many Hemerocallis species can easily be transported long distances with high survivability and adaptability. This is especially true of some of the fulva group, but also for several of the yellow species. This leads me to suspect that original species ranges have long since been blurred. For that reason, I prefer to look at the species of the genus Hemerocallis in the most minimalistic terms. It is important to stress that this is not a scientific thesis, but rather a collection of my thoughts and observations about the genus Hemerocallis and the pre-domestication materials that we might refer to as 'the species'. 

I am making no attempt here to lay out a new understanding of the speciation of the Hemerocallis. I am intentionally using the most minimalistic way of understanding the two categories that the species fall within - "orange" and "yellow". This allows me to speak in more general terms and leave specifics to those with the expertise to pursue such matters.

While I may discuss where I think species boundaries may fall in some instances, this will not be my primary concern in this article. Much more work needs to be done on the phylogeny of the Hemerocallis before we can make any certain statements, but based upon current models, we see two major divisions early on in the Hemerocallis - orange and yellow. Another split seems to consistently lie within the yellows creating two major sections of yellow flowered types, but from which no clear patterns of phenotype emerge to me, as yet, with those said to clade together. I will give more consideration to possible species with the yellows than I will with the fulva group, as I think the only speciation within the fulva group is toward H. sempervirens and H. aurantiaca (or away from them). Otherwise, I think the fulva complex is composed of regional variations and garden selections - forma - not subspecies or species within an over-all 'fulva umbrella'.

I do acknowledge that there are likely to be several species amongst the yellow branch of the Hemerocallis genus. However, I think the fulva clones (or forma) all comprise one species with many regional and garden variations, clones or forma (forms). I do think that H. sempervirens and H aurantiaca are offshoots of the fulva complex, though they also could represent ancestral, evergreen types. I simply do not know, but would encourage research to elucidate this relationship more fully. Perhaps these are in the process of speciating or perhaps they represent older, evergreen ancestral forms. It is interesting to ponder. 

I do suspect that sempervirens and and/or aurantiac are of fulva origin, one way or the other, and they group with the fulva in the clades I discussed in part 1 of this series - What is a Daylily? The Genus Hemerocallis. As I am not a phylogeneticist, I am making no attempt to reassess the current species designations, but it seems some reconsideration may be necessary in the future. That however will be up the the phylogeneticists. I will use the species names as presented within the paper from which it derives, when discussing species. 

That does not mean that a plant labeled as one species is the same exact clone as that used in another project and called the same species: there is much regional variation between species, and there are numerous forms of the species in commerce and agriculture, as well as the variations that occur naturally within the wild populations of the species. I must stress that I find the entire species structure of the Hemerocallis to be tenuous, formed on the old field-identification methods of the last three-centuries, as it is. 

Now, with genetic analysis we can make much more certain comparisons, and no longer need to compare visual presentation in an attempt to determine relation. We can begin to look beyond form and understand the actual genetic relationships. With that said though, much more extensive research is needed to unlock a broad-based phylogenetic analysis. What we have now in the papers listed at the end of Part 1 is a good beginning to point us in the direction of further research and give us a starting point to piece together this complex web of relationships.

In the papers I cite at the end of Part 1 concerning the phylogenetic trees of the Hemerocallis species, there tended to be two major splits - orange and yellow - the fulvas and all the yellows comprising two different major clades. Then within the yellows, there are typically two major breaks with several species in each branch. 

Tomkins showed H. citrina vespertina to be at the base of the separation of the yellow and fulva types. The vespertina species may be suggested then to be older than other yellows and may be ancestral to all of them, as McGarty suggests in his analysis Phylogenetics, DNA, Classification And the
Genus Hemerocallis. Further data may refute this, but the phylogeny that the Tomkins tree presents is certainly suggestive and interesting. 

Some of the yellow forms are nocturnal, but certainly many are diurnal. The plant of H. citrina vespertina that I grow is nocturnal. My plant derived from Joseph Haliner. I can say nothing as to how this plant would compare to the plant in the Tomkins study.


My plant labeled H. vespertina, my accessions notes say: 
mid-July, 4" Flower, 64" Ht, dip, fragrant, 30 bud count

I have seen much higher bud counts, and scapes taller than 64". It is a massive plant with presence, though the tall scapes do not hold up perfectly and need to lean against a fence or other tall, sturdy plant. It likely grows in tall mixed field settings and woodland borders in the wild. Its leaning scapes help to dissipate its seeds further afield. We often grow this type by tall orienpet lilium to provide trellises to the scapes. In breeding, crosses to modern cultivars with strong scapes gives offspring with strong scapes, though usually shorter than the vespertina scapes. Vespertina adds branching and bud count to the offspring. I have counted as many at seven and on rare cases, up to eleven branches on vespertina.


I have no way of analyzing whether vespertina is ancestral to all the yellows or not, but it suggests fertile ground for future research. It is an interesting finding and may be a place for future researchers to apply some focus. I hope to see more in the future on the relationship of this clone to the other Hemerocallis. In the meantime, it is an interesting garden subject and well worth growing, in my experience.

The next major split in Tomkins would suggest that H. citrina is older than and possibly ancestral to H. minor, H. hakuunensis, H. dumortierii and H. middendorfii, while on the other side of the split is H. lilioasphodelus and it is shown to be older than and possibly ancestral to H. thunbergii and H. dumortierii var. Sieboldii. 

In Genetic and Phylogenetic Relationships of Genus Hemerocallis in Korea Using ISSR by Choi, et al., the phylogenetic tree shows fulva and fulva for. kwanso as clading with H. middendorfii, while H. dumortierii clades with H. thunbergii and H. minor. Another earlier branch from the yellow group give H. coreana and H. hongdoensis, both Korean forms that have been given species status.

In the paper Phylogenetic Relationships of the Genus Hemerocallis in Korea using rps16-trnK Sequences in Chloroplast DNA by Man Kiu Huh, et al., There are three phylogenetic trees presented. The first tree is a ps16-trnK analysis using MEGA5 and shows H. fulva var. kwanso at the bottom position within the tree. From there a branch occurs that contains two forks to H. coreana and H. aurantiaca, while another branch leads to all the yellows - H. minor, H. littorea, H. thunbergii, H. dumortierii var. esculenta and H. dumortierii. H. coreana and H. aurantiaca usually show the dark 'gold' coloring that is similar to the center petal pigmentation of many fulva types - rich in carotenoid pigments.

In the second phylogenetic tree - rps16-trnK analysis using PAUP 4b10 - the divisions occur in the same manner as in the first tree from figure 1. 

When the third tree is formed using PAUP 4b10, we see a shift of the layering of some of the forms involved. While the yellows hold their form from the other two maps, the positioning of H. aurantiaca, H. coreana and H. fulva var. kwanso shift, with aurantiaca at the base, coreana representing the next branch and fulva var. kwanso next and from there the large group of yellows branch off. Even with these discrepancies, we can still see that the basic break of "orange and yellow" holds up fairly well.

In synopsis, it is my view that these relational phylogenetic trees give us a glimpse into the evolutionary history of the genus Hemerocallis. Each paper reinforces the notion of the two main groups - orange and yellow. 

The fulva complex represents the use of both carotenoid and anthocyanic factors to make the more heavily pigmented flowers which include visible eyes and midribs. Both the under layer of carotin within the petal and the top layer of anthocyanins are present in most examples. Some forms in the var. rosea category within the fulva complex show reduction of carotene within the petal and a change from the typical orange pigment to a visually pink pigment in the petals. Other forms show intensification of red, while other forms show particularly bright and clean orange tones. Yet others have a purple overlay and present a brownish, fulvous coloring. Fulva complex forma are almost certainly responsible for the majority of anthocyanic colors and patterns seen in they highly-selected hybrid garden daylilies.


H. fulva var. 'Europa' 

The yellow flowers show various levels of changes from the flower color of the fulva group. The most conspicuous change is that the surface anthocyanins seem to be lost and so the under pigments in the middle of the tepals is highlighted, becoming the "coloring" of the flower, the exact tone depending on the combination, presence and/or absence of carotenes and other yellow/gold pigments. 

These flowers appear 'self colored' or solid in color and range from darker, orange golds (H. middendorfii, H. coreana, H. hakuunensis) to medium yellow gold (H. dumortierii) to yellow (H. minor, H. citrina) to light yellow (H. vespertina and H. citrina forms) to very pale yellow (H. citrina 'Baroni', other H. citrina clones). It seems to me that the range of yellows may have to do with the removal of carotenoid pigments found in the tepals that create the deep orange/gold/yellow coloring of forms such as H. dumortieri or H. middendorfii and underly most fulva forms, creating a rich pigmented area under the upper anthocyanic layer within the main body of the tepals in most fulva forma. 

As these pigments are knocked out, the lighter-appearing yellow pigments are expressed without any interference - sort of a natural "color clarification" process. The palest forms of citrina and vespertina would then represent the most reduced pigmentation amongst this group.


H. dumortierii with its golden yellow flowers.

H. citrina - one of four clones obtained from Joseph Haliner. This one shows medium yellow flowers.

H. vespertina first year of flower at about 4' tall. In the second year, this plant produced scapes over six feet tall. The flower is a lemon yellow with a hint of creaminess. Hemerocallis vespertina is my favorite of all the yellow types.

Another form of H. citrina from Joseph Haliner. This one is much larger, more trumpet shaped and extreme nocturnal. The flower is much lighter and fades to an even paler yellow than in the picture above. Picture at sunset.

It seems to me then that the yellow flowers represent a loss of pigments as compared with the fulva types. It is a common phenomena to find simple knock-out genes that stop the production of a pigment early in the developmental chain. I suspect that a major evolution from the pigmented fulva types to the yellow flowers is the shift from obviously pigmented to subtly pigmented, and may represent an evolutionary shift from daytime orange ancestors to nighttime palest yellow forms as one of the major splits within the genus. 

Many pollinators, both diurnal and nocturnal, see within the ultraviolet range. Photos I have seen of self-yellow daylily species flowers under ultraviolet lighting show intense eyes and midribs, as strong as in any fulva, but in a different range of colors tending toward blue/purple as the ultraviolet lighting reveals the pattern. I do not know if there are any forms of the yellows that do not show eyes under ultraviolet lighting, but I think that is a question someone should be looking into and would make an interesting study. 

TO SEE A SIMPLE YELLOW DAYLILY UNDER ULTRAVIOLET LIGHT
I highly recommend taking a look.

This link takes you to the blog Photography of the Invisible World and specifically to the blog post 

Hemerocallis (Day Lilly): human vision vs simulated bee vision; reflected UV ultraviolet photography

Another excellent photo of yellow Hemerocallis under ultraviolet light can be found HERE. This link leads to the article: A deadly passion: moths and their attraction to artificial light- July 27, 2015by Eric Dillalogue. This article discusses the nocturnal pollinators - moths.

If the yellow Hemerocallis all have ultraviolet patterning, then we may have to think of all daylilies as "eyed", with those that appear non-eyed maybe just representing a knock-out gene that removes the pattern from human-visible anthocyanins, causing the same pattern to be created in some other way, but invisible to animals within our visual range. We are not historically their pollinators, so they don't really have to flash their eyes at us, after all. 

Ultraviolet spectrum lighting can reveal the presence of the same eyes and even midribs on the 'self yellow' flowers, so is the pigment anthocyanin responsible? Or are we seeing some other effect? Has the anthocyanin simply been blocked/removed, or has it been only been changed in some way? Further, the extreme change from heavily carotenoid "gold" to medium yellow and then on to light yellow may also represent loss or change of pigments. Here we may be seeing a series of knock-out genes that make flowers lighter and lighter by knocking out the production of carotenoid pigments. Building on reduction of both anthocyanin (at least out of the human-visual range) and carotenoids may well be the pathway to creating the palest flowers, what we might call "clarification factors" in the flower-breeding hobby that give rise to many of the colors seen in domestic hybrid lines that are the furthest departures from the ancestral sources.

So, what advantage could the lighter flower hold for survival? Another area where the two types split is periodicity of the flower. While none last more than a day, there is the distinct split between diurnal and nocturnal types. All of the nocturnal types are yellow and most of them are on the paler end of the color spectrum, though not all the yellows are nocturnal and both the diurnal and nocturnal forms can show the ultraviolet eye pattern. The fulvas are diurnal for the most part. If H. vespertina is the oldest of the types as suggested by Tomkins, then the major break would be between diurnal high-pigment flowers and nocturnal low-pigment flowers, each utilizing the pigmentation that serves to best attract pollinators in the light conditions in which the bloom opens.

However, at this time, that is pure conjecture. We do not know if vespertina was the ancestral style of the yellows, nor if the yellows have interbred with the oranges at times in the past giving rise to hybrid populations of orange and yellow that may still be with us as some of the current species. Clearly hybrids of yellows occurred - citrina is often self-sterile, for instance and Tomkins lists it as base to several other species. Yellow could have emerged without nocturnal behavior, certainly. Perhaps several types of yellow arose over time and some of those became nocturnal (and paler - less pigmented) over time as they colonized new niches. I hope to see much more lab work done of the Hemerocallis genus.

The evolutionary point of the pale nocturnal yellow flowers with their stunning array of ultraviolet patterning is to attract the attention of night pollinators - generally moths. They also exude a sweet smell to make themselves more attractive. The day-blooming fulva do not tend to have any fragrance and rely on a completely different group of pollinators. While we don't think of fulva being fertile due to most of us having H. fulva var. 'Europa' as our reference point, the fulva complex contains many fertile forms and is an ancient breeding population, not just one big, ancient vegetative clone. The many forms of fulva that we know of occur precisely because the fulvas have been a breeding population for a long time, generating new and novel combinations. 

Mixed fulva seedlings

All the phylogenetic trees seem to indicate that the split between the yellows and oranges is quite old, and such a split to allow the exploitation of two different environmental niches would allow genetic drift from the ancestral base by limiting the possibility of inter-breeding between night and day populations including the fulva group, except perhaps in rare circumstances. This is the very type of thing that drives speciation, as the restriction of gene flow would allow for the emergence of distinct populations. I am not saying this is how it happened, only that it makes sense from an evolutionary perspective and is a well-known driver of diversification in many species. The key to becoming a species is to keep your gene pool closed. The orange fulva group and the nocturnal yellows seem to have been fairly good at separating themselves through this process. Diurnal yellows though may naturally cross with orange types when bloom occurs in close enough proximity in space and time.

However, keeping the gene pool closed is obviously not something that has been as successful within the yellow group. Some of these types appear to be self-incompatible and thus must outcross with a different form of their own species or another species or species hybrid in order to produce viable seeds. One of the most important comments in Tomkins is the last sentence of the last paragraph of the paper, "citrina is self-incompatible and any variant arising from it would have to be obtained from an outcross. Thus, these early species variants may have arisen via cross-pollination or they may represent distinctly different genetic types". In other words, we don't really know, but we are beginning to get a window into the process.

What does seem to be clear is that 1.) there are some old, base types within the yellow category that likely represent species, 2.) all the yellows are closely related and likely share a common ancestor that broke off from the orange fulva group a very long time ago, and 3.) the actual web of relationships - what are the old base forms and what are hybrids of those or even of yellows and oranges - is not fully determined but seems to offer fertile ground for further research.

In addition to the change from orange to yellow, there are other interesting changes from the majority of the fulva group to the yellow group. One major change is that the fulva category all are rhizomatous to one extent or another. This is a good survival strategy, as it allows the plant more 'mobility' within the environment than clump formers who must depend on seed spreading to move about the environment. Rhizomatous growth is often a mark of a generalist species. Clump formers are more place-dependent, relying on other forces to distribute their seeds in order to move from place to place over the generations. Both strategies work and rhizomatous growth does not rule out sexual reproduction. However, all yellow types are not clump-forming, with some of the yellow species able to run, though none as vigorously as the more robust fulva types.

So we can assess several major diagnostic traits found within the genus Hemerocallis. They are: 1.) the presence or absence of water-soluble anthocyanic pigment in the upper, surface layers of the tepals, which is visible to the naked human eye, 2.) rhizomatous growth versus clump-forming, and 3.) diurnal versus nocturnal flowering. 

The first trait (anthocyanic pigment) is fundamental to the split between the 'orange' fulva group and the 'yellow' group. Rhizomatous growth is most common in the fulva complex and its relatives such as H. sempervirens and H. aurantiaca, but is also seen in some of the yellows such as H. lilioasphodelus. We can then say that most yellows also tend toward clump forming rather than spreading, rhizomatous growth. The third trait, nocturnal and diurnal flowering also tends to split along the color lines with the fulva group tending to be diurnal. Yellows are both diurnal and nocturnal, but we can say the majority of nocturnal forms are found amongst the yellow group.
H. vespertina clump

These three trait sets alone represent a wide range of diversity and show several levels of adaptation and response to environmental, geological and evolutionary imperatives. They show one group adapting into available niches over a long period of time and changing in response to changing environments throughout their long history in Asia. This diversity has made the Hemerocallis genus fairly generalist and adaptable. The few that might now be considered specialists are the exception.

I have not yet discussed foliage habits in regards to the species. I would like to look at foliage a bit now. As I discussed in Part 1, the Asparagales that the Hemerocallis arose from were tropical plants in a warm, tropical forest planet. These would have had little need for any genetic ability to withstand cold, temperate climate and would have probably tended toward an evergreen/ever-growing growth much as we see in current 'evergreen' daylily cultivars and Hemerocallis species such as H. aurantiaca and H. sempervirens, as well as Hemerocallis relatives such as orchids or agave.  The change in environment that brought about the formation of the Hemerocallis would involve adaptations to survive cold, as the entire evolutionary history of the Hemerocallis is intimately tied to the long plunge into the ice ages. 

When I look at the fulva complex, most of the plants are actually some form of "evergreen" and are not fully deciduous unless they are frozen off. That is, they will continue to grow to some extent if weather conditions are good, though they do not show the continuous growth of sempervirens or aurantiaca. They are 'conditional' in that they have to reach a certain level of cold to have their leaves die and then stop growing, appearing to be dormant and often forming resting buds in the north, but requiring little in the way of triggering to return to growth. Any dormancy in these Hemerocallis seems to be very dependent upon the environment. 

Northern growers regularly tell me that this or that fulva is a "hard dormant", while southern growers routinely tell me they range from "semi-evergreen to evergreen", depending on the form. The more evergreen and tender forms like sempervirens and aurantiaca will often suffer winter damage, with sempervirens being the least tender of the two. It is slow growing in the north, but it does survive without die-back, while aurantiaca will frequently show die-back from freezes.

The other fulva types tend to be much less bothered by cold, but are not necessarily frost tolerant. That is, their foliage may be killed or damaged by late freezes, but tend to recover quickly. Bloom may be effected by late freezes, as many of the fulvas bloom fairly early in the season. There are some notable late blooming examples though, such as Hankow and sempervirens, and their flowering is not typically effected by late freezes.

The foliage of many the yellows tends to follow suit with the fulva types, being conditional and responding to the environment. Much like fulva forms, the citrina, vespertina, altissima types I have grown were conditional in their dormancy, remaining in growth up to certain temperatures and then once frozen off, going into something like a dormancy, while in milder years remaining in an evergreen state and not going dormant. However, many growers in the south tell me these are "evergreen or semi-evergreen", while Northern growers often call them "dormants". 

The large dark green foliage of H. citrina vespertina and H. citrina, back right and back left. Domestic cultivar in foreground right.

I have witnessed both types of foliage behavior from the same species clone depending on climactic and weather conditions. However, here H. dumortieri is fully deciduous every year and forms a resting bud under the past year's dead foliage that persists through the winter and comes out again the next spring with little variation, generally appearing in March/April. While this looks like a true dormancy, it may not be. It could simply be an artifact of environment. 

The subject of foliage is something I wish to leave to the experts to decide. It is a complicated subject and is best left to those who are trained to make educated assessments. What I would like to look at is the utility of developing coping mechanisms if you are a tropical forest lilioid grass moving into a long, cold age of the earth that will proceed in fits and starts for several million years. Your coping strategies must revolve around ways to handle the cold. You can let your leaves die and maintain the roots and crown. If you funnel resources into making the roots frost resistant and thus able to survive freezing weather, and give up on the leaves, you can preserve energy and persist until better conditions for growth.

The development of frost tolerance would have been driven quite simply by intermittent cold periods killing out those individuals that could not survive. The colder the temperature fell, the more tender material that would be removed, except in refugia where very ancient lineages of the original ever-growing/evergreen type could potentially persist. This selective pressure would have seen the survival of those most able to handle the cold, a natural selection toward cold-hardiness, both through coping mechanisms and evolutionary changes. One excellent way to do that was to rest in a dormant-like state from which growth could be reinitiated quickly and loss through extreme freezing is only a setback; thus the main plant can persist and regrow rapidly.

Over time, changes could allow for greater frost tolerance in some lines, as well as a variety of "dormancy"/deciduous triggers to initiate rest, whatever that might actually be. I look forward to further research and invite all research into daylily foliage behaviors. I do think there are more extreme versions of dormancy in the deciduous daylilies that should be looked into. These may not represent true, classical dormancy, but may still be fully replicable and reliable traits that are expressed over wide environments. Only time and more research will tell.

The age of the Hemerocallis genus and the period of its evolution into the modern world leads me to believe that there are many possibilities, and likely more than one set of mutations, involved in foliage type and behavior. It seems to make the greatest amount of evolutionary sense to me to maintain the ever-growing traits of earlier ancestors while also being able to survive cold and freeze, mimicking dormancy for necessary periods, in some instances even going so far as to form something like resting buds, and still be able to grow quickly when the right environmental factors are present. 

To me, this conditional, ever-growing type that can stop or slow growth based upon environmental conditions and that can survive cold and freeze, loosing foliage through deciduous action or freeze damage, and then resting until the proper trigger-level of light, water and/or warmth returns to initiate growth is the most natural path an ever-growing/evergreen would take to survive in a cold world. In this way, it has mechanisms to cope with both environments when they are presented and is as such a generalist, being able to exploit a variety of major environmental challenges.

H. sempervirens

All the forms of dormancy and/or winter/cold coping strategies that we may witness in the Hemerocallis would be an evolutionary response to the environmental changes that drove them to emerge from their early Paleogene Asparagales ancestors - increasing cold and the responses that would allow those in the path of that cold to survive, where access to southern tropical and semi-tropical refugia were not available. It is unknown if there are any remnant populations that represent primitive forms. Sempervirens and aurantiaca may be late branches off of fulva that are adaptations to a warm climate and only resemble older, root forms in their evergreen growth habit, but even sempervirens will go into a partial dormancy and appear dormant in very cold frozen conditions. 

The Hemerocallis species have become as we see them through a long period of climactic change. They have made adaptations to exploit various ecological niches as the great tropical forest of the early Paleogene gave way to the drier and less-forested world of the ice ages. The landmass of Asia, showing less cooling than other parts of the earth, has provided a perfect environment for both temperate and semi-tropical forms of Hemerocallis to persist and thrive over a very long geological age. The earliest splits of type are very old and seem to revolve around flower pigmentation and time of flowering, as well as clumping or spreading growth-habit, while intermediate types may represent hybridization between any of the root forms. 

Once man became able to intervene in the destiny of plants though, the nature of the evolution of Hemerocallis would inevitably change, with both the production of food and the desire to collect exotic flowers being ancient pursuits, especially in Asia. I suspect that domestic selection has given us some of the more interesting things we see in the fulva group, while natural variations in ancient lines could have naturally produced doubled flowers or naturally more pink or red flowered individuals. Any effort by early Asian farmers or plant collectors to bring these types together could have resulted in lines where selection and improvement could have occur. 

The same is true for the yellow types, especially the citrina type which has been in domestic production for centuries and is recognized to occur in many forms in various regions. Improved clones are even offered in Chinese agriculture. Other species of yellows must have undergone a great deal of domestic selection over the centuries as well, especially where they are used in agriculture.

Next time we will look at the domestication of the daylily in ancient times and how that lays the groundwork for the modern garden daylily.

H. fulva var. 'Korean' (Seoul University - Apps)