I know this horse has been beaten to death, but looking at all the misleading info about the two on the internet I thought I would help confuse everything even more. Now it is pretty well know (even on the web) that Kwanso is a double and Flore Pleno is a triple, so actually it sounds pretty easy to tell them apart. Until, you start looking and the doubles to most people would look like triples the way the center is formed, still double and triple by looking closer (side by side) is a distinguishable difference.
Even in the ATP data base looking at the pictures I am not sure they are all correct, even the height for Flore Pleno shows to be 30 inches, there is a comment saying that it should be much taller. I think some of mine have nearly reached four feet, so is it Flore Pleno or is the data base wrong, or was it 30 inches in the garden of the person who entered the info?
I have been looking at these for a while and I have two plants in my garden that I believe to be Kwanso and Flore Pleno, growing side by side. I have not entered any of the pics in the ATP data base because I was not sure because of a few discrepancies. So let me ask what you think.

Kwanso: Smaller bloom, less petals, bloom often looks distorted to some extent, and the foliage is bushy looking and short.


Flore Pleno: Much larger bloom, the bloom is more well defined and seldom has the deformed look of some of the Kwanso blooms, the foliage has a very upright tall classic fan shape of a daylily. Often grows very tall in my garden.


Pictures of the two side by side: Flore Pleno on the left, Kwanso on the right;


Flore Pleno on the Right Kwanso on the left;


Kwanso in a pot;


Flore Pleno Bloom;



If these look correct I will enter some photos in the data base.

Good idea. Those are lovely lilies. I especially like the last photo, but some of us are pretty ignorant in that department. (I didn't even know that doubles and triples existed.)

I would be interested in getting both of them. If anyone has them for sale or know someone that does.

It really helps to see them side-by-side like that! It sure looks to me like you are right about which is which. Have you tried to count petals, also, to see if they match what others have said - that Flore Pleno will have about 18 petals, Kwanso about 12:

http://garden.org/thread/view_...

I have Kwanso and I see both doubles and triples with them. IMHO Flore Pleno us prettier but Kwanso does have it's charms. Such vibrant colors on both.

So do I, Celia. Both doubles and triples on Kwanso.

Good to know that - I'm assuming both also find Kwanso to be a shorter scape with lower, bushier foliage?

I hope everyone's information makes it to the database. As long as it's stated as a grower's own observation, in a comment under the cultivar, each note may help sort it all out eventually, and make it easier for everyone to approximately ID what they might have. The kwanso/flore pleno confusion comes up a lot.

Daylily (Hemerocallis 'Flore Pleno') versus Daylily (Hemerocallis fulva 'Kwanso')

On the other hand, even if it was finally decided by DNA ... there might be no telling who has what, other than the particular fans that are tested for a DNA match. I think there will be a fairly long time before anyone can be more certain than they are by simply weighing any consistent differences in characteristics between the two.

There is little to no difference between the two as far as fans/foliage and height are concerned. The only obvious difference is that most Flore Plenos have a darker marked design on the blooms. It's a subtle difference in the coloration. Mine are in bud but not in bloom; I'll have to wait to get images to show you what I'm talking about.

Cool! It helps so much to have a side-by-side visual comparisons. I ended up giving my kwanso-or-flore-pleno away this spring because I didn't have an easier way to compare what the differences were. I didn't want to chance having the very, very fast increasing one in the flower bed, though I don't know if rate of increase might also be the same between the two.

I've never had reason to study the rate of increase, but I can tell you I got them at the same time and they are running a close race for increase. The height is determined more by location in relation to the sun, because they all get the same nutrients and same soil quality. They don't all get the same sun, though. Some have taken up residence beneath a smoke tree that grew like a gigantic giraffe this year in all the rain. They look to be a little shorter than the others and are shorter than they were in past years -- shade from the smoke tree is my guess.

I've had both, but I left my Kwanso behind at my old house. My Flore Pleno currently have scapes but are not in bloom yet.

My "Kwanso", that is what I am calling it, gets very tall also, but the foliage on my plants is definitely different! Does any one else notice this. In the photos I think the "Kwanso" plant is actually taller than the "Flore Pleno", the "Flore Pleno" I gave away were much taller.
Sharon said:
"There is little to no difference between the two as far as fans/foliage and height are concerned" is your foliage the classic fan type on both or is the foliage the lower bushier looking foliage? So Kwanso has both double and triples and the petal count doesn't mean anything? Now I am more confused than ever! There is a definite color difference even in some of the "Flore Pleno", some have much more yellow in the color of the petals. Are the blooms on the two types of plants you have also the same size? Looking at the data base the colors vary greatly within the same type of plant. I know my camera cannot catch the true colors at all, is DNA testing necessary to distinguish between these two, does anyone know exactly how to tell the difference?

Zencat,
How do you tell yours apart? Do yours both have the same type of foliage?

Kwanso is the only one I have so I can't answer as to foliage. Mine gets quite tall but I have it in afternoon shade.

Zencat,
I am not trying to be a pest, but how did you determine it was Kwanso? I wonder if half the people selling these two know the difference, and I am just assuming there is a difference.
https://classygroundcovers.com...
http://www.rhs.org.uk/Plants/9...
http://www.sunnyborder.com/pla...

Look at your first and last links, Seed, they call them Hemerocallis 'Kwanso' flore pleno-- all in one. You're right. They don't know the difference.

I've never looked beyond the difference in color and that Kwanso is sometimes only double and sometimes triple. Here's Flore Pleno from years ago. I'll continue to look for an image of my Kwanso. They are usually the last of my daylilies to bloom.

I'm also beginning to wonder what the difference truly is.

Stout bred doubles using both flore pleno and kwanso. He studied them and classified them both as para -doubles.

This is how he described a para-double:
"Having at least some well-formed stamens or petaloids with some traces of anthers. Usually there is duplication of petals or petaloid stamens. There is abortion or sterilization of the pistil. Such a flower is sterile as a seed parent."

He also described the differences between the two cultivars:
"A comparison of the flowers of the two clones, Flora Pleno and Kwanso. The flowers of the Flora Pleno Daylily ... in comparison with those of Kwanso ... have a greater number of well-formed petals, the number of stamens and aborted stamens per flower is less, and the pistil is more frequently fully aborted or not in evidence. The central column of the flower is shorter and the flower is more compact."

It is probably extremely difficult to identify the two cultivars unless one has them growing in the same conditions and unless one takes numerous measurements and counts of different characteristics on substantial numbers of their flowers and then does statistical comparisons.

admmad,
Thanks for that info about the blooms, I wonder if he mentioned anything about the foliage?

Maurice, thank you. You said it much better than I did. I wondered what Stout did with them and if his results confirmed any clarity of their differences. Mine grow side by side and in groups. I have to wait till they bloom before I can see much difference and then only in the bloom itself.

His words 'the two clones' should give us a hint, therein lies our confusion. . . probably.
Thank you so much, Maurice!

I'll have to examine my "Flore Pleno" more closely when it blooms, to make sure it IS Flore Pleno!