Monday, May 10, 2021

Getting Clear about Color

Getting Clear about Color

The daylily occurs in a wide array of colors. The potential for combinations and interactions of colors is vast. In addition, in some types, multiple colors can appear in blocked areas like eyes and/or edges that contrast with the main petal body. While the genetics and pigment pathways found in daylilies is much more complicated than what I will be discussing here, I am still able to describe the most basic functions of the main pigments and how they interact, to help the average non-chemist or non-geneticist to begin to grasp what they are experiencing when they see the colors of a daylily flower, and what they might produce from various crosses in their seedling beds. This article is not meant to be a discussion of either the science of the pigments and pigment chain reactions that make daylily colors, nor is it a discussion of the genetics that lie behind the colors of daylily flowers, though both subjects may be touched upon in a cursory manner. 
A very interesting phenomena is how the visible colors in daylilies are formed by two basic sets of pigments, and while there is a lot more at play, these two basic sets of pigments encompass a great deal, perhaps the majority, of what we see. The carotenoid/lycopene pigments occur in the lower layers of the petals and water soluble anthocyanins occur as a layer in the upper surface of the petals. This combines to make a color visible to our eyes through the blending of the anthocyanin in the upper layer over the carotene or lycopene in the lower levels of the petal. So the carotene or lycopene interacts with the anthocyanic pigment color on the surface to create the apparent tone and shade of color that our eyes perceive. The green in the throats of some daylilies is likely based in chlorophyll.
There are probably several major gene mutations responsible for the variations seen in carotene and lycopene. There are two distinct forms of "yellow" or carotenoid pigment, and either can be lightened or darkened by genes which modify the carotenoid pigment present. When I observe those with carotene, I divide them into 'gold' and 'true yellow'. In private communications with a researcher who has done the laboratory work to find the differences in the carotenoids of various non-anthocyanic flower types, commonly called "yellow", he reports that, "...those without anthocyanins I divide into those with violaxanthin which is "lemon yellow" versus those with zeaxanthin which are ... "yellow orange." His "lemon yellow" is the same was what I have referred to as "true yellow" and his "yellow orange" is what I called "gold" or "golden yellow". Both types can be converted to lycopene, though it is not clear if the same gene effects both forms of carotenoid equally, or if each has its own unique gene causing it to become lycopene. Both types of carotene and lycopene can be very intense and dark (think Mary's Gold or Orange Velvet) or very diluted and light (think So Lovely or Arctic Snow) depending on what modifier genes are found in conjunction with the violaxanthin or zeaxanthin or their lycopene counterparts. There is a huge range of tones in between the darkest and lightest versions of each. It seems to me that both types can be extremely lightened or darkened, depending on how the pigment is modified. There are undoubtedly other pigments at work, such as chalcones and flavonoids. If there are independent major genes for each of these pigments, then there are also likely minor gene/modifier genes and epigenetic effects that modify the expression of those major genes.

Carotene and Lycopene variations

The anthocyanic pigments, found in the upper petal layers, produce colors we perceived as red, orange, pink, lavender, purple, sand and brown tones, and near-black tones. The appearance of these pigments can vary widely as different types of anthocyanins interact, and depending upon which version of carotene or lycopene the anthocyanin is layered over. The potential for visually perceived colors and shades is vast. One marvelous achievement of modern breeders has been to breed and select flowers that have a combination of background color and anthocyanic layer that make for very clear colors to our visual perception. The lightest background combination of lycopene/carotene and a low number of different types of anthocyanins seems to me to make the clearest colors, as we perceive them, with the least amount of interference from tones that will lead toward brownish or grayish coloring effects (triads - three or more colors combined). 

Anthocyanin variations

It is important to understand that the visual effect of daylily flower colors is just as one would expect from the color theory that underlies all art and design. While the genes that produce the pigments that we perceive as colors have nothing to do with the way the colors mix, in the sense of art and design color theory, as the genes only determine the heritability and production of pigments and chemical pathways and reactions, so the colors that we see actually have nothing to do with the genes of the plant, in the sense that no gene produces a "color". What the genes produce are pigments that our eyes perceive as various colors, and when those pigments blend and interact, they create colors that we perceive as blended tones (non-primary colors). The colors are perceptions of our brains and as such are somewhat subjective. 

The perception of color interactions in the daylily flower is our eye relaying information to our brain, and so a color and shade and tone is perceived. Variations in ocular physiology and brain function can create different perceptions between different people. The colors and color interactions being perceived by our eyes is the secondary effect of a pigment layering process that the genus Hemerocallis uses to attract pollinators in their native environments. The colors produced in nature are those most amenable to this process. We have combined mutations and disentangled the pigments that the species use to extract individual colors (specific combinations of pigments) such as bright pink or purple, where in the wild they don't occur in a way that is so 'clear' (single or only a couple of anthocyanin pigments with proper background carotene/lycopene pigment), because they don't have to for their natural purpose. The pigments are creating the effects we perceive, and so to get a specific effect, you will need specific pigments combined in a specific way, but those pigments are not the same as the colors we see, and the genes that produce the pigments are even further removed from what we call "colors". As an example, there seems to be a gene that produces an anthocyanic pigment that we visually perceive as orange, and so orange daylilies such as H. fulva 'Europa' are not exactly just yellow daylilies layered in red pigment. So while the color orange is made by combining red and yellow, in daylilies we get a pigment that is orange as one of the types of anthocyanin. I know this is all terribly semantic and pedantic sounding, but there really are distinct differences in each thing - genes, pigments and colors.

Click image for larger version

Another example is purple. There seems to be a type of anthocyanin that visually appears to be purple. The color purple is made by blending blue and red, but daylilies seem to have a gene or combination of genes that produce visually purple-appearing anthocyanin. So a purple daylily is not just a red daylily with blue blended over it. So in both of the instances I have cited here, those colors are created, in a round-about way, by genes that produce pigments, pre-blended by nature, to appear to our eyes, due to wavelengths of light hitting our eye and being carried into our visual cortex - finally perceived by our brains as a given "color". However, where the colors of daylily flowers do work like color theory is that if you have that purple-appearing pigment layered over a medium to dark yellow, your visual cortex tends to perceive a brownish tone, while if the background color is a pale form of lycopene or carotenoid, a cream to pale yellow, the purple layered over it will appear much more purple, and it seems that the clearer and paler that background color, the clearer the purple anthocyanin appears to our perceptions. 

Phoenician Royalty

Further, if we add two or more types ("colors") of anthocyanic pigments, and depending on what the carotene/lycopene background is, then we see visually blended colors just like we would expect from color theory. Whether that then appears "clear" or "clean" in coloring depends on which colors are combined,  just like in color theory. As an example, when you have purple anthocyanin and orange anthocyanin present in the same flower, you can get rusty-orange to reddish brown colors (though there does seem to be an anthocyanin that makes visual brown on its own). The background of carotene/lycopene will make a difference in the brownish tone of an orange/purple.  An example of this type of effect can be seen in some of the brownish/rusty orange variants of H. fulva. 
The anthocyanic species daylilies all show a visual combination of background and upper layer pigments that result in slightly 'off-tones', which in fact are combinations of two colors that interact in a way that makes an intermediate tone rather than to let the upper tone dominate and appear to be a single color, so for instance, none of the H. fulva 'rosea' are what we might call "clean pink", because they seem to have a fairly dark undertone that has a lot of yellow color in it. This then gives them a slightly peach hint that anyone who is able to perceive a lot of shades of color will pick up on. I always see it, but I still love the 'rosea' types, because they opened the door for so much and because they all tend to be a lovely shade of coral/peach/pink that I find quite nice in and of itself. 

H. fulva var. rosea

To me, a single color is when you have just one primary color. That would be yellow, red or blue. There is no yellow anthocyanin that I know of, but we do have a whole range of yellow shades and tones created by the carotene pigments. Red in its purest expression occurs in petals and eyes and edges of some hybrid cultivars and a few cultivars have a nearly perfect self-red coloring (the cleanest, purest reds seem to be layered over pale creamy lycopene backgrounds). Red in the species is limited to some eyes and then is in tomato to burgundy shades of red. Blue doesn't really exist in daylilies in a stable form as yet, but there are some very bluish expressions of purple and lavender. So from the beginning, we have little true primary coloring in daylilies - yellow from the true yellow carotene and red in anthocyanin. 

The three primary colors

Secondary colors are those made from combining two primary colors, so blue and red make purple, while red and yellow make orange and yellow and blue make green. Those can all be lightened or darkened in tone, but pink does not seem to be just a dilution of red, though you can get light reds and plants that have flowers with both red coloring and pink coloring combined and in various shades. It seems as though the existing anthocyanins are based in orange, red, brown and purple/pink/lavender (which may or may not be separate genes or a continuum of expression of a single major factor which can be modified), and finally, very dark blackish pigment (which may be a combination of several of the other types, intensified). Some of these may not really exist and may just be modifications of one of the other anthocyanic pigments. In practice though, they do exist visually in the hybrid daylilies and the majority of the colors we see in daylilies are secondary colors. That is the colorists perspective. In daylilies though, all the basic anthocyanins are considered pure tones by some. To me they aren't but that is being nit-picky. I will occasionally see people discuss 'primary colors' in daylilies, but upon further questioning they are actually referring to primary and secondary colors. "Jewel tone" colors often seems to me to mean the same. What I think that means in practice is one or two anthocyanins which blend properly (not becoming brownish) combined over a base of some tone of carotene/lycopene that does not interfere or interact negatively.

The combination of three colors is called a tertiary color, because the mixing of three colors (a triad) is one way to get tones that are no longer really any of those colors but fall into intermediate colors, often in the range of cream, tan, sand tones to brown and gray tones in our human visual perception. While there appears to be an anthocyanin making visually brown pigment that derives from certain fulva species, brownish effects can also be achieved through combining the secondary colored anthocyanins (i.e., orange and purple), or by combining purple anthocyanin over a dark yellow or golden yellow carotene. On some yellows, purple may only make a subdued purple that isn't bright but is still recognizably purple, while in other instances the visual effect is more brown. The presence of visual anthocyanins in general seems to be dominant to the absence of visual anthocyanin (i.e., yellow/melon types). I don't know if they are all alleles of one locus or independent genes.  

Tertiary colors are derived from blending the three primaries or by blending a primary with a secondary color.

Pink and/or lavender anthocyanin over yellow or gold carotene can create shades of peach to orange visually. Lycopene without anthocyanin though also seems to be able to make a range of peach tones, so this color family can be created in two entirely different ways, it seems. When the under-layer is a darker lycopene and the anthocyanin over-layer is pink or lavender, the outcome can be fairly peach to orange, as well. Orange anthocyanin is complimentary over yellows and gold, but they can also occur on the lycopene base and can occur on the very diluted near white bases. Red anthocyanin can work on yellow carotene or lycopene bases. The carotene/lycopene base plays a part in the particular 'tone' of red you see. On a yellow background, there is a tendency toward a more orange tone to the red, though this can vary and some red daylilies might have both red and orange anthocyanins interacting to make them more orange-red or China red. Red on a lycopene base can be rather coral when that base is intense and the clearest reds appear to be on the lightest lycopene base.  All the anthocyanic colors appear to express, with the least interference by a third color, on the palest lycopene "near-white" to "cream" bases.

A good example of pink anthocyanin over a yellow carotenoid base creating a visually peach tone.

I see expressions in cultivars and in the seedling bed that indicate to me that there can be more than one type of anthocyanin present at once. I do not know if this is from two different alleles at the same loci being present, heterozygous and perhaps showing co-dominance and partial penetrance of both types, or if this means that each of the anthocyanins actually represent a different segment of DNA, being their own individual genes. If the later is the case, there might be the possibility of having more than two types of anthocyanin present at once (could this be what "black" is?), and if these mutations are each at separate alleles, whether on the same chromosome or not, there is the possibility of having each gene either heterozygous or homozygous in any combination of all those separate genes producing a particular anthocyanin. Think about what that means for color. The anthocyanic colors seem to be orange, red, purple, brown, and pink/lavender. I honestly don't know if purple is the same gene as lavender/pink or if lavender is the same gene as pink only modified differently, or if pink and lavender are separate genes. All of the anthocyanic colors seem to be able to be lightened or darkened, and I would suggest this is due to factors that control the level of pigment deposited in the tissue of the tepal and perhaps the distribution of pigment in the tissue (or both).  I doubt that these are the same genes that create dilution or intensification effects in the carotene/lycopene, because you can have darkly intensified anthocyanin on a very pale carotene/lycopene base, and conversely, a darkly intensified carotene/lycopene base with lightened anthocyanin over it.

The Spice Must Flow, with a red-orange and a purple parent, combines both colors in the flower and is difficult to photograph, as it tends to flatten out into brownish tones, when in person it is much more vibrant and shows both orange and purple tones to the eye.

So if we have orange and purple anthocyanin showing up in the same flower, regardless of the shade, this will tend to produce a brownish effect, in some shade, perhaps leaning more to orange or more to purple, but noticeably not fully either one (a tertiary tone), though in rare cases both colors can be noticeable to the eye. In those instances, these combinations can produce layered effects where both the orange and purple are visually present and the flowers look vibrant in person, but can be very difficult to photograph. A homozygote for both orange and purple would be able to provide all its seedlings with a heterozygous dose of both orange and purple, and those heterozygotes would be visually in the range of the homozygote parent, but could produce both orange and purple individuals when mated to either color. The result of the visual coloring, tone, would depend on what background carotenes or lycopenes are present and what shade (diluted or intensified) it is occurring in. If you know the color wheel, you will be able to deduce what the combination of the various possibilities might make. If you get too many anthocyanic colors combined, then all roads lead to brownish colors and if the brown anthocyanin itself is also present, then the tones are dulled leading to earth tones regardless to the other colors that might be present.

But are the brownish tones something "bad"? Clearly nature doesn't think so, as the pigments found in fulva, made by the anthocyanin layered over the carotenoid layer, tends toward orange, brownish-orange, brownish-red and peach-pink to sandy-peach. In domestic hybrid breeding, as the pigments have been pulled apart and layered over cleaner and cleaner backgrounds, I believe we have gained an understanding of what is actually present in the genus and what each of the anthocyanic pigments can look like independently on a very pale lycopene pigment base. The 'brown' color can be diluted or intensified. It can occur with eyes, edges, watermarks and patterns. Some of the effects can be very awesome and create a neat niche of domestic cultivars that have interesting garden uses. While those who can only think about the "clearest colors" may find them painful to look at (and we recognize and honor your pain!), there are a number of daylily people and gardeners alike who appreciate the unique effects that can be achieved with colors other than "jewel tones". The range of cream to sand to brown to black, as well as their grayed versions, are awesome in certain landscape uses. Further, such plants can have a lot of applications in hybridizing, and can even produce very "clear and clean" tones when mated to the proper partners, especially if their earth tones are the result of heterozygous gene action.

Brown Exotica

One of the biggest problems concerning color in the daylily world is that there has been a certain 'looseness' used in the descriptions of color for a great many registered cultivars over the years. The use of the terms 'white' and 'pink' and 'lavender' have often been extended far past the point that I would use them. Because of the focus on getting to the clearest and brightest colors (which is a worthy and noble undertaking!), there has been tremendous peer-pressure in the daylily world to get away from earth-tones or anything species-like. The general public's extreme reaction to fulva 'Europa' as an "exotic invasive" must have also played a part in this process.  However, the brown factors have persisted, and our refusal to acknowledge them as a part of the overall palette is a big part of the problem. Because of the general peer-pressure to only produce "clear colors", a flower that should be called sandy-tan with a brownish-burgundy eye, might get registered as 'near white with a wine-purple eye'... I don't blame the registerer for using more appealing terminology, and I don't blame growers for being dismayed when the flower doesn't match the description (or the introduction photo). What I blame is a mindset where "sandy-tan with a brownish-burgundy eye" isn't perfectly good enough, though I do think hybridizers might have a responsibility to describe colors as accurately as possible, in spite of the general peer-pressure of the group hive-mind. I don't know of any other group of flowering plants where such good pigmentation for brown variations occur, and where the breeders are also so generally ashamed of it. The orchid growers have certainly made good use of the color brown, as have breeders of many iris species. The carnivorous plants often show an array of interesting brown tones. Daylilies could have this exploited much further than it is.

Brown Orchid

Near white with black purple eye and edge above green throat? Not in my garden, but still beautiful.

Now I want to state very clearly for the record that I LOVE the bright, clear tones that have been achieved in the modern hybrid daylily gene pool. 

Jennie Sivyer

Cultivars such as Rosy Complexion (John and Annette Rice) or Hush Little Baby (Sarah Sikes), Blue Dolphin (John and Annette Rice), Violet Blue Note (Robert Selman) or Willow Dean Smith (John and Annette Rice) are true achievements of color breeding. I think that the selection and breeding toward this kind of color clarity is a work of art.

Rosy Complexion

Such brightly colored flowers glow in the landscape, and when combined with bright to light yellow to near white or cream colored cultivars as a background planting, can create a cheery, magical landscape that simply takes you out of the everyday world and into a world of fantasy and sensual pleasure.

Hush Little Baby

But that doesn't mean that the other expressions of color which fall outside that narrow range are by default rendered inferior. They serve other purposes, and the purpose of any garden is as individual as the gardeners who make them.

Forsyth Pale Face

If you can only appreciate the bright jewel-tones and have no room or time for anything else, that is wonderful and I couldn't be happier for you! Nor can I express how special I think that is! But I do think that it is yours, and doesn't have to be mine.

Barbie's Dream Flower

I also like the brown underbelly of nature, and not just the few bright high-points along the way. Shadows make the light seem brighter, and the dull and earthy has a special beauty all its own.

Matthew Martin

Some What Odd

Wabi Sabi

Again, for the record, my favorite colors are jewel-tone pinks (of every shade and tone) and purple to lavenders in the bluest possible tones, along with near-white, rounding out the top three. The next group of favorites, for me, are the brown and gray tones in all shades, followed by bright medium to pale yellow shades and tones. Orange is the next favorite group, with red and golden yellow coming in last. The majority of my program, in terms of my desires in regard to color breeding, is based in breeding the clearest lycopene-based near-white, and then working pink and purple in every shade and tone, as well as the other anthocyanic colors, over that near-white base. That is the ideal in my program for coloring. However, because I have worked with so many different types of plants to bring in superior plant traits such as rust resistance, thrips resistance, vigor, size, tall scapes, branching, superior plant performance traits, etc., I have perforce had to deal with using plants with flowers in colors that I like (there are none of them that I don't like), but that aren't at the top of my list for preference and that are a carotenoid base rather than a pale lycopene base. 

First generation (F1) crosses of Ancient Elf (a medium golden yellow carotene based) x Solaris Symmetry (diluted lycopene base with lavender anthocyanic over-layer). Click image for larger version. Three of the seedlings from this cross are 2021 introductions - Ancient Ent, Origin Of Symmetry and Sun Dragon.

Second generation (first generation backcross BC1) from seedling (Ancient Elf x Solaris Symmetry - now Sun Dragon) x Solaris Symmetry

This has allowed me to see a wide range of interesting heterozygotes, and to learn how to use those intermediate, heterozygous expressions in breeding. In the process, I have come to love grayed-lavenders and lightened brown on lightened lycopene backgrounds more and more each year. I have also learned that there can be tremendous breeding potential in heterozygous plants that don't match the ideal of "jewel tones". Because I like all the possible colors and shades and tones, and I love the species daylilies, keeping and working with plants that have flowers that are not the clearest possible pink or purple or lavender has not caused me any undue stress or suffering. In fact, I have learned from it and gained both important data and useful experience, along with an appreciation of a wider range of phenotypes of flower coloring.


There is a lot to the genetics and pigment chemistry of daylilies that we don't fully understand yet. Much can be deduced from simple observation. The colors, once the genes and pigments have produced them for our eyes to see, blend in the same way that we would describe in color theory, as used in art and design. While many have very narrow ideas about what "should" or "shouldn't" be allowed, acceptable, or permissible in the colors of daylily introductions, the fact is that an entire range of colors exist, including brown and grayish tones. All these colors exist, and so all can be used, cherished, loved or reviled, as one may choose. The important thing though, in my opinion, is to get clear about the nature of the range of colors that exist and to not attack and demean colors we don't "like" or people breeding colors we don't prefer. Useless terms like "muddy" or "jewel tone" are not good descriptors and the many different ways in which each are used shows us that there is no real consensus about what such terms even mean. By understanding what colors are, how they are formed, how our eyes and brain perceive colors and what that means in our daylily flowers, we can get clear about color.